Here's a good energy saving tactic with leftists: never give them the answer to two questions in a row, be quick to answer the first question, then ask yours. If they ignore it, don't let them get away with it or try to divert from it or move into something else, express how disappointing it is they aren't answering a question and signal the conversation is over if they won't, and explain that's why you're not addressing anything else of theirs until they do. More often than not they get huffy and keep insulting you, and if that's the case you can say something like 'i was hoping you would be an adult about things' and then just leeave all their insults hanging and don't let it get to you. That burns them up so much because they're left looking like a fool.