I'm not comparing myself to lower rated players, I'm comparing lower rated players with experience on map x vs lower rated players who have never seen map x. Even if I'm playing a map for the first time versus someone who plays it frequently, I'm at a disadvantage. Just have a look at my BO in my first actual attempt at a game on Amoor:
https://replay.faforever.com/23837156 (minute 5 3.8k score, 6 land facs, 17 tanks)
and then my second BO on Amoor:
https://replay.faforever.com/23837606 (minute 5 4.8k score, 7 land facs, 23 tanks)
And it felt good playing it a second time. The first time I played against someone way more experienced and got my ass kicked, but learned from it.
I get that not everyone wants to have this same experience, but it is intended to be a competitive matchmaker, so that's kind of the experience they signed up for.
Also to loop back to Sheppy's point, mapgen openings definitely have a pattern to them and so people who religiously play 3v3 TMM have an advantage over those who are new. In addition to this, toxicity definitely still exists towards players who misinterpreted the map and their role in the game. Very sad example: returning pro player Crazed plays his first mapgen game, hasn't been on faf since https://replay.faforever.com/24511266
And finally, Sladow's post (which is what promped me to make my post) mentioned trainees, which are by definition players who wish to learn and improve.
In any case I do agree it's kind of "too late" to change 3v3 queue to contain man-made maps because it would upset a lot of players who want to play just mapgen