There are a ton of reasons not to support Bernie Sanders and though the arrogance, idiocy, misogyny, and racism of a HUGE CHUNK of his supporters isn't the most important reason not to support him, it is a big part of why I support him to win the nomination. (It's interesting to me how this is a mirror of 2008. In 2008, the PUMAs turned off a lot of Democratic voters and help drive them to support Obama instead of Clinton. In 2016, the Bernie Bros are turning off a lot of Democratic voters and helping to drive them to support Clinton instead of Sanders.)
But here's the thing. Despite the fact that I think he would stand no chance of winning if he gets the nomination (he'd be eaten alive in a debate with Trump and we would all have the pleasure of seeing commercials crying 'Socialist!' 24/7, particularly if he doesn't change his stance on financing and he runs out of funds in mid-September), despite the fact that I think he would be an absolute disaster as president (the man's signature accomplishment in 27 years of being in the House and the Senate is that he never changed his party affiliation - there isn't one piece of legislation he can point to and say 'Me! That happened because of me!' and just look at the hissy fit he and his campaign threw when CBS wanted to change the opening of the last debate from the economy to terrorism - being able to rapidly adapt to changing circumstances is one of the most important qualities needed in a president, and he has repeatedly demonstrated that he lacks that ability, not to mention that he has repeatedly shown that the slightest bit of criticism sends him flying off the handle, and any Democratic president is going to get tons of criticism), I will vote for him if he is the Democratic nominee and support him if he is the president.