It took some doing, but I can be tenacious. Still had to do a feedback form to get out of timeout.
TOS Terms Of Service. "In any content that you create or modify while using this website, do not discriminate against any sect, commit illegal acts, advertise, harass others, or otherwise make it less fun for other people."
That covers a lot of territory. If someone threatens, intimidates, or stalks you, you have recourse. First, read the actual message. Does it violate anything in those terms of service. If you feel they are intimidating or harassing you, or being abusive, and can describe what it is, you have a clear TOS violation. Flag it. If it continues, keep flagging. Chances are, they are doing the same with others. If so, flag those actual incidents. It's best not to reply to these users, because they're laying a trap. The worst you can do to them, directly, is to ignore them altogether. The only way they find out is when they can't meme comment or have to wait hours between comments.