Could Someone Explain This?

From my understanding, the way matchmaking works in relation to premades is that if a team has a larger premade, their average mmr is lower than the enemies to balance things out. Here's my issue

You solved the macro problem on a team-based level, Riot. But what about that same system that allows a diamond to lane against golds or even silvers just because they are playing with a couple bronze players? Sure, looking at the team as a whole they might seem balanced. But what about the dude that has to lane against someone clearly better than him just because of premades? It just seems unfun and unfair on a micro level, and we all know league is full of both macro and micro aspects and both can influence the game's outcome. You can't overcompensate on one side just to even out a disadvantage on the other side, that isn't true balance