How to deal with people?

Tl;Dr: How to stop rude people from being rude? I just had a game as Lucian, Silver 2. I did pretty well early game coming out 3/1/1 in laning phase, and as I started to roam after taking tower I became 5/2/?. Then it gets into late game and I am getting stomped. I end game at 10/10/9. However, the entire game I had a lee sin who was making rude remarks. The game started as we where about to leash gromp and he said that we where cancer. Nothing had been said in chat yet by me lee or blitz. Just poof, time to be an asshole. I ignore it, go to lane, do some stuff. Once we developed a clear lead he stopped being rude because we where winning and who complains when winning? But their team just scaled/performed better than us and got their lead back. We pull off a pretty nice baron steal where blitz grabbed their ww over the wall so he couldnt smite and lee hopped in and smited, yeah he died but #worth. But OBVIOUSLY it was the teams fault that he died. I ignore him, move on and we group mid and charge. Their ww hurts mind you, one ult and im dead, and WW shows up mid during a fight and as an adc should be, I was in the back. But he came from behind so I ran away and got chased to bot lane and he wasnt chasing anymore, so i used baron'd minions to push a tower. I get the tower and ww shows back up but i bush juke him and head back up to my team, where they all die because they reengaged. So now its just me 1v5 against their team and our base has an inhib and nexus, one nexus tower. We lose no matter what at this point so i go balls to the wall and burst jinx before the game ends. Post-Game screen and Lee is calling me brain dead, said that I should drink bleach, or cut off my balls. Now normally I don't get too upset by this stuff but I had lost 2 games prior, all of which had rude people. I understand that they are going to be here but why on earth do they go to such extremes to say things like that and just make gaming an unpleasant experience? To anyone that actually read all of this thank you, i needed he venting, and hope that I can climb the ladder to where people rage because im doing bad and not because they are an A-hole.