What you said is half true. Yes, you said yi can easily be countered in plat+. This is true. No you did not simply argue that point alone. It is incorrect, arrogant, and flawed thinking to assume that it is always a player's fault for having a problem with a champion. Again, as I stated before, I might know perfectly well how to deal with (zed, yasuo, rengar, yi, insert "op" champ here - not necessarily actually op, just considered op). But if I have 4 teammates who draft stupidly, feed all of laning phase, don't group or split or collapse properly (whatever the correct strategy is depending on the champ), then I can't 1v5 no matter how fed I am. I could spend all game hunting the yi - and fall behind in lane because I'm running bot/top/mid/jg all game trying to kill yi, or i could win my lane. And that's all nice and good. But if 4 opponents win their "lane"/jg, I'm not going to out-teamfight 4 fed enemies if my team is that dumb. It doesn't matter what you tell people in bronze-gold. You can explain thoroughly NOT to force a fight because you are going to clear a giant wave, pull 2 people bot, and then tp to force a 5v3 baron the enemy team can't contest and they will still jump in on the first yasuo tornado they land on the other team and die 4v5 before you can complete a tp - costing your team baron, stopping you from killing bot inner tower (because you aren't an idiot who's going to finish it off and die 1v5), and potentially costing the game.
Git gud has nothing to do with such a game. It literally wouldn't matter if you are plat or diamond; you would lose such a game - you have such games at those ranks too. Four stupid teammates is 4 stupid teammates; there's no way around it. I can work with people who lose lane, down in cs, and 1/3/0 kda or something like that. No problem. But if they want to draft like shit, split when they need to group, never ward, never take an intelligent fight... a well coordinated team outweighs individual talent. Just look at when clg has won lcs - they didn't have individuals steamrolling their opponents 1v1 or 2v2. They had coordinated teamwork giving them the edge in every little skirmish and fight. Same thing applies to solo queue. Don't go assuming someone is too dumb to know how to deal with "OP" champ just because they say they don't like the champ.
I used to ban singed, not because I couldn't deal with singed, but because I'd regularly have my jg and mid running around chasing him all game instead of getting shit done on the map. Or I'd ban kha'zix because I know my teammates will run around alone on adc or squishy midlaners facechecking bushes instead of group up. Does that mean I need to "git gud" and learn how to deal with kha? No - I know how. I'm banning or complaining because my TEAMMATES don't on a regular basis. Don't assume to know whether or not this is the case about the player simply because they make a comment about an "OP" champ. That's all I'm saying.