I've always taken the word "leftist" to mean a die-hard supporter of left-wing values, even when shown how ridiculous and extreme they are. Much like the far-right will cling to extreme ideas that have no place in a modern society. Both use dishonest tactics to try and subvert the other.
As for evidence tea party crashers exist, simply go to google or YouTube and search for them. You'll find plenty of examples.
As for evidence tea party crashers exist, simply go to google or YouTube and search for them. You'll find plenty of examples.