I don't remember what the exact post said but this didn't seem like a case of abuse. She blew up over nothing and told him that if he leaves it's over, so he acted with immaturity and left, so she blocked him out of spite.

In most relationships, if you care about the person and the break up was as ridiculous as theirs, you'd want to reach out to make sure they're okay and see where you both stand. Not an A move to try to reach out once, because you never know how it can turn out. People overreact and blocking someone on social media while you're an adult is pretty immature (unless it's for reasons you state above where they're genuinely in danger and need to separate, but that isn't usually the case, and I don't believe it was the case here) so talking to her to find common ground and see if you can come to an understanding or get closure before moving on is normal and natural. When she said 'no leave me alone' that was that and he should've left her alone.