I don't mind losing. There are better players, better teams, better team compositions, naturally. Someone has to lose the game, sometimes it's me, sometimes it's the opposing side. But seeing the winning players typing stuff like "easy" or "rekt" in all chat after beating you, without you taunting them in any way, is just a slap in the face and it discourages me to play more.
if you're winning the game, no matter how hard or close, just don't say anything in all chat apart from "good game, well played" when it ends, and either talk shit in your own team chat or keep that in your head. Seeing an opposing player trying to disrespect you is not something that makes us wanna play more games.
just say "good luck" at the start and "good game, well played" or "thanks for the game, well played" when it's over. Leave the rest elsewhere.