One time I sent a dm to someone who was mass downvoting in my communities and just asked what was up. They then commented somewhere in some thread, saying that it was so inappropriate for me to send an email asking them why they were downvoting so many things. And lots of people were agreeing with them. So in my experience, sending a DM is not taken very well. So I don't. I just ban.
But hey, if you hate every single thing in my community, then you shouldn't be upset about being banned from it. You hate it anyway, right? :)