Yes, everyone has bad games, but after a certain number of deaths like 2-3, you need to try to stop feeding so you can help your team.
This is kinda different, but I was playing a bot game with a friend and we had 3 bots on our team. These bots did literally nothing but feed all game, and they decided to feed the enemy Karthus bot. I picked Illaoi and my friend picked Lux and literally every time Karthus ulted, Lux lost like 90% of her health because of how strong the bots made him and how far behind my friend was since they were new to the game.
My friend died a lot in this game simply because our teammates fed hard. It wasn't that she played badly, it was cause our team had made the enemy team so strong that even messing up once meant she died, which as a new player, she was bound to mess up occasionally.
Again, this was a bot game, but it was a bot game that took 44 minutes that I had to solo carry because three people on my team were too busy feeding and the fourth was still learning how to play. This game ended with us winning. The bot team had 72 kills to our 47.
Every death makes the game harder for your team. Even in a bot game where you can play stupidly OP champions like Illoai and 1v5 penta kill them due to their programming not thinking her ult is something they should avoid, it's still insanely hard to win if your team isn't trying to help.
Imagine if this was actual humans that were smart enough to know to walk out of my ult, who were smart enough to go take Dragon/Baron while we defended our base from the super minions that were spawning at 14 minutes in, who were smart enough to chain CC on me so the only threat in the game was eliminated.
Flaming is always wrong. It doesn't matter what the person is doing, flaming them is not going to make it stop or fix the situation. The best you can do in situations when people are flaming you is mute them and then report them, since they will probably not offer any useful advice after that. It is unlikely that people will ever stop being toxic to each other, so best thing is to ignore them and just enjoy your game.
However, normally this flaming comes for the person just wanting to win, and they see you as a thing preventing them from winning. If someone is flaming, unless it's for some stupid reason ("Useless fucking support took 1 CS, I'm AFK, enjoy loss %%%got."), they most likely have a point that they aren't getting across right ("FUCKING BOT LANE ALWAYS FEEDING." which should be "you need to play safe and stop dying, you are losing the game for us.")
either need to be able to survive better in early game or allow them a proper chance for late game to come and early game champions would actually get a proper impact by poor 'power' in late game.
