Is this about Quick Match or Hero League?

I haven't played enough Hero League to really comment on that. I'm rank 14, but play sporadically in it and don't have a great grip on how competent I feel I am in relation to my teammates. Sometimes I play with people who are really good, sometimes people not so good, but never anyone who is just learning. I only have maybe 60 or 70 games there, so I don't know what I'm seeing for sure. But never have I seen a rager target someone in Hero League who is just "happy to be playing and learning."

In Quick Match, I will say that the most consistent ragers I have met after about 1,000 games since last May are people who, in Starcraft, would say things like, "Gold league macro, diamond league micro!" They think they're better then they are and suffer from moderate to serious Dunning-Kruger. The most mean-spirited and hostile players, I look 'em up on HotsLogs after games a lot of the time just to see what their deal is (any games submitted? Estimated MMR? Hero w/l?). Almost always in the 1,800-2,700 range with under 300 games played. I should have built a spreadsheet to track this, but I always forget... They prioritize the wrong stuff, dive and die unnecessarily, blah blah blah. The number of people I have played with who are just obviously brand new is really small in comparison. It's legit fair to say that a better experience for all players is had when matchmaking puts like MMR with like MMR, but there are gonna be new players at low MMR who are assholes from other games and experienced players who are assholes to people who are also experienced but on a new Hero or having a bad night, etc. Other games, where people might be matched more evenly, are notorious for being even more hostile. So I think this is more an asshole problem with assholes looking for an excuse (not you, OP, but in-game I see a lot of, "Waaah, why am I playing with these bads? GG Blizz" stuff. In League, they'd just cry about Elo hell instead.)