I read an article a while back that I can't seem to find atm that said that many socialists thought Bernie was too conservative for them and he panders to the Democrats too much.
Probably the same crowd that thinks Palestine is more important than Social Security and Medicare
Is that really any less irrational than Republicans who think Israel is more important than tax reform or protecting the Second Amendment?
As for the comments about socialist/Leftist parties in the US, part of the reason socialists never gained a sustainable following in the US was precisely because the American socialists were so much more radical than those in Europe. A lot of the European socialists who opposed building coalitions with "bourgeois" reform movements emigrated to the US. Combine that with the fact that American industrialists were often even more hostile to socialist activism than conservative European aristocrats were (hiring private security guards to gun down striking workers, for example) and you ended up with an American socialist movement that was very violent, anarchist and confrontational in nature.