It's not inherently the nature of the game. It's the nature of matchmaking.
I played HoN before matchmmaking, and it was quite interesting: you created a lobby, people would join, and you as leader could vet your teammates and kick the ones you didn't want to play with. Then the game proceeded once both sides were happy.
It took about ~10mins to get a game going, but the games were far higher quality.
I played DOTA back in highschool and HoN for the first year or so. The toxic nature of the DOTA community has nothing to do with matchmaking. You can certainly filter people in your own games, but that only identifies the people who are so socially inept that they can't make it to the start-game-countdown without being a jerk. In the WC3 era, people left during the 5 second countdown (i.e. after attempting to ensure they were not jerks) so often that the various hosting assistance programs would watch for it specifically.
The real hazard in DOTA / AOS / MOBA games are the people who slowly (or quickly) transform from quiet or reasonable people into insanely angry trash talking monsters. After all, the DOTA community got its reputation for being awful back in WC3, totally independent of any matchmaking.
I played HoN before matchmmaking, and it was quite interesting: you created a lobby, people would join, and you as leader could vet your teammates and kick the ones you didn't want to play with. Then the game proceeded once both sides were happy.
It took about ~10mins to get a game going, but the games were far higher quality.