Why do lobbys get balanced by rank and level?

I notice that it often balances teams by lvl, 1-2 gold borders on 1 team then u get 1-2 golds or 3 silvers on other team etc. Makes games where everyone is bronze border besides me just kinda feel like crap troll games. Games with higher lvls seem to always be closer matches with people actually trying to work together for a win and arent toxic. though I guess that last part is why many of them are on alts in first place.

Its like a high lvl game with few to no bronze borders and its instantly has people trying to build a comp, fill gaps and rolls etc. Low lvl game if anyone talks and isnt just all instant dps locks its usually cursing, harassing or just dumb lude comments. This of course isnt every game, nor or all high lvls not the same as low lvls, there are also some really good low lvl people to play with. Its just after playing tons and tons of comp this is kinda the general way things feel for most games. I could practically just turn chat off if I see mostly bronze borders and back on with a higher lvl game and it would be for better most the time.

I don’t think level matters for competitive matchmaking.