"We recognize that, in the next four years, our decision may cause us to have an even more difficult time. But we believe that this will give us a chance to recalibrate, and the Democrats will have to consider whether they want our votes or not."
That's gotta be one of the strangest reasonings I've heard in a while.
I was a Sanders supporter in 2016, but when Hillary got the nomination, I supported Hillary. Would I have preferred Sanders? Sure. Otherwise I wouldn't have been a Sanders supporter. However, you don't always get exactly what you want and you often need to deal with whatever hand life has dealt you.
In 2020, I again supported Sanders, but again switched - this time when Biden got the nomination. Same reason this time.
The people who refuse to support a candidate because they don't think that candidate is 100% perfect aren't seeing reality. You can't let the perfect be the enemy of the good.
By refusing to lend support to a good candidate, they risk allowing a terrible one to get into office. And when Trump is in office and decides that all Muslims aren't US citizens anymore and must be deported, will these people say "but at least we kept Biden out of office"?