Tbh both ways are wrong, sana and slash thinking they know stuff when they dont (advicing on content they dont clear/struggle) and players speaking truth but in a harsh manner, so first thing first:

1- Stop advicing on content you cant clear/struggle, that just spreads the missinfo further and increases the bad reputation hbc already has in terms of kh ignorance.
2- Choose the words wisely when speaking trush, as some1 said, without insults.

If point 1 is satisfied, people wont have any need of calling some1 out and will give advice as such without insults, cause you know, they get pissed when people think they know stuff when they actually dont.