It was the same in the UK. Labour (left wing party) lost the election big time. Despite the obvious swing to the right they decided that the problem was that th

It was the same in the UK. Labour (left wing party) lost the election big time. Despite the obvious swing to the right they decided that the problem was that they were insufficiently left wing and ended up with Corbyn, who is the Bernie Sanders of the UK. That's over simplifying a bit, "they" in this case was a flood of new party members who weren't previously involved, but could be similar.