Last night on Twitter I said a few things about the “Bernie Bro” phenomenon — the hostility and abuse that folks have been getting recently in online spaces when they express criticism of Bernie Sanders or his candidacy for president — and I want to say a bit more about it today.

My own experience, and it’s shared by a lot of other people, is that this is real, and — in this campaign cycle — distinctive. I get more crap, and more aggressive crap, when I say something negative about Sanders (who I’m likely voting for) than I do when I say something negative about Clinton, and I’m more likely to have my motives questioned when I do. When I tweeted a few things a week or so back about Sanders’ ill-phrased Supreme Court tweet, a bunch of people showed up to tell me exactly what was wrong with my tweets, my character, and my intellect, including several with high follower counts who I ordinarily don’t interact with.

So why is this happening? I have a hunch.

In 2000, there was a tremendous amount of animosity between Gore supporters and Nader supporters, with a huge amount of vitriol being expressed on both sides. Same thing with Clinton and Obama in 2008 — lots of ugliness, lots of anger flowing in both directions. This cycle there’s some of that coming from the Clinton camp, but it’s not not as much as is coming from Sanders supporters.

To put it another way, what’s weird is less what Bernie’s people are doing than what Hillary’s people (mostly) aren’t.

If you look at Nader 2000, Gore 2000, Clinton 2008, and Obama 2008, one common factor, absent in Clinton 2016, leaps out: They all thought they were the underdog. They all thought they had a shot to change the world, and they all thought they were getting screwed out of that shot by the system and their opponents. Nader was running a third-party campaign in a country where the major parties conspire to keep third parties down. Gore’s people were scared that Nader was going to tank the election for them. Clinton was battling to be the first woman president, facing all the misogyny that went with that, and Obama was in the same boat with regard to race. In each of those cases, for the supporters of each of those candidates, victory was close enough to taste, and the prospect of defeat was too bitter to bear.

Which brings us to 2016.

For Clinton, there’s far less cause for anxiety than there was in 2008. She entered the race as a huge front-runner, and she still holds that position. She’s got more experience in both campaigning and governing, a much bigger advantage in cash and endorsements, and a far weaker Republican field to contend with if she makes it to November. She is, by just about any analysis, the clear favorite to win both the Democratic nomination and the presidency. Bernie Sanders’ campaign, on the other hand, is right where all the others were in 2000 and 2008. He’s underfunded. He’s widely reviled or dismissed by powerful forces in the media and his own party. He’s fighting an uphill battle against the DNC and Wall Street. And as the country’s potential first Jewish president, he’s facing no small amount of ugly bigotry along the way.

Sanders’ supporters see victory as almost within their grasp, and a lot of them think that if he loses it’ll be because the presidency was stolen from him. They’re simultaneously ecstatic and terrified.

And sometimes — as we saw eight years ago and eight years before that — people in that frame of mind wind up freaking out and doing stupid and obnoxious things.

Not all of Sanders’ supporters are acting like jerks, of course. Most of them, the huge majority, aren’t. But some of them are. Enough of them to be a problem.

Demographics play a role in this as well. Sanders’ support skews young, which means there are more of his partisans in the social media spaces where the worst of this kind of obnoxiousness tends to take place. The most vocal jerks among his supporters also include quite a few white men who are happy to deploy racist and misogynist attacks against those they disagree with.

It’d be a mistake, though, to attribute the obnoxiousness of Sanders’ worst followers purely to the demographics of his base. Yes, Sanders’ support skews white and male, but Clinton still has enough of a lead nationally that in raw numbers, the two candidates are running pretty much even among men and among white voters.

Sanders presumably leads among people who are both white and male, and even more so among young white men, but those differences aren’t staggering — Clinton has plenty of young white men in her camp, and it’s not just (though it is disproportionately) young white men who are engaging in this behavior. My strong suspicion is that if the underlying dynamics of the race change — if Sanders, say, wins Iowa and New Hampshire and then goes on to pull out a third straight victory in Nevada — we’ll see the vitriol from his camp decline and that of the Clinton camp rise, even if their supporters’ demographic skews stay pretty similar.

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When I talked about this stuff on Twitter last night, one of the most interesting responses I got — and I got it from several people — was the argument that this stuff shouldn’t matter in the election, because people shouldn’t be basing their votes on which campaign has the worst supporters. This struck me as wrongheaded in a few different ways.

First, there are reasons to talk about this stuff other than its horse-race impact. If it’s true — and I believe it is — that Sanders’ supporters are disproportionately abusive in online settings, that’s not just a problem for Sanders. It’s a problem for the people who are being targeted, and Sanders supporters may be in a better position than others to assist them. Those of us who support Sanders’ campaign can help address this problem, and if we can, we should.

And even if we think people shouldn’t change their votes on the basis of the actions of online jerkery, elections aren’t determined by how people should vote. They’re determined by how people do vote, and whether they vote at all. And if people’s experiences online make it less appealing to be a Sanders supporter, less comfortable to associate with that campaign, that’s got the potential to cost him votes. Even if people don’t jump ship to Clinton because of it, some may stay home, or volunteer less, or opt out of discussing their views with their friends. The Sanders campaign is a grassroots campaign, and grassroots campaigns need all the enthusiasm they can get.

I’m seeing far too many people spending far too much energy trying to convince folks that their experiences with Sanders supporters online aren’t real, or aren’t important, or shouldn’t be discussed. Nobody’s going to vote for Bernie because someone tells them they’re wrong to be angry about this stuff, or that they’re lying about it, or they’re stupid if they let it affect their vote.

That’s not how you build a movement. That’s not how you make a revolution.