i rewatched ep 1 and i'm still confused as to why yuuri's friends would be so mad at yuuri for skating victor's stay close to me?
It was because Yuuri has learned the perfect copy of Victor’s performance instead of working on his own routine - in their opinion he was wasting his time, doing unnecessary things instead of working towards his future and creating and perfecting routines for future competitions.
They were worried for his future, because they felt he wasn’t doing what he was supposed to - he wasn’t training his own skating, he was copying and memorizing someone else’s work. (they might not have been fully aware that Yuuri needed that to get back his love for skating. if they knew, perhaps they would look at the whole thing in a different way)