Is it normal? Yes. Is it acceptable? No. Is it reportable and against the rules? Definitely yes.
LoL has a history of being known for a very toxic community, especially in newer player games and low ELO. Things like crude insults, saying "kys", or racial slurs are much more common than some other communities (or real life for that matter). If you are a new player, I'm sorry that this is the impression you are getting for League. It's honestly a good game and people get better behavior wise as you climb, but it's no secret that people can be extremely mean.
If this sort of thing pops up again in games, which it most likely will, the best option is to mute the player and then report them at the end of the game in the after game lobby.