Why Should What Someone Says Here Have Anything to Do With Whether One Votes?

[TwilightZone]

11. "where that number is probably very near 100%"

That's a bit optimistic. His supporters on DU are indicating that they'll vote for Biden because that's part of the terms of service of the website. There are a significant number of them who I'm reasonably certain won't. They're pretty easy to spot. Some of them have been here for years.

"maybe because it isn't what they're saying"

I disagree. Some of them are stating it quite clearly. I'm also pretty certain that this OP is in response to one doing exactly that.

"Bernie bashing"...

is, for the most part, a knee-jerk comment made regarding any criticism of Sanders, however mild. Do some people cross the line? Certainly. But there are just as many people who compulsively call anyone who posts anything critical of Sanders a "hater". When was the last time you saw a Biden supporter non-ironically call a Sanders supporter a "hater"? It's a childish insult and I don't think the posters have any idea that it says way more about them than it does their target. Same goes for "Bernie bashing". It's an overly simplistic, all-purpose, meaningless response.

"can't stand the attitudes they've seen from some of his supporters"

There's a significant difference, as far as I'm concerned. The Biden supporters who exhibit this behavior do not reflect their candidate. On the other hand, much of the nonsense posted by Sanders supporters is straight out of the horse's mouth and/or is promoted by his staff or prominent surrogates. Hacking at the Democratic Party, promoting doctored videos of Biden indicating "dementia", constantly parroting the "where is Biden?" nonsense, etc.

For the most part, the Bernie or Busters - and there any many more of them here than you apparently realize - were never going to vote for anyone other than Bernie. That hasn't changed and it has nothing to do with anything anyone says on DU. It has to do with their candidate spending years calling VP Biden and the rest of the non-Sanders Democrats "corrupt" and undermining their support, entirely by design.