Rant about vs Katarina Game (just venting)

We're in a Bronze 1 game my team comps are:

Caitlyn (myself) vs Sivir Nami vs Thresh Cassiopeia vs Katarina Jarvan vs Vi Jax vs Garen

Karatina got fed and started destroying in team fights. I told my team: "Jarvan save knockup for Kat's ult, Jax save stun for the same, Cass save ult for the same, Nami save bubble and wave for the same, the only real damage dealer is Kat, as everyone else in their team is fairly behind."

The response from my team was: "shut up noob"

Why are people like this? Was what I'm saying unreasonable?

Just wanted to vent so thanks for listening (reading)