last time I was farming my unarm skiils on top of the tree but someone said it was to op and not allowed so I ask it to you guys.
I'm not sure, i reckon the person who said it to you was lying though, but i don't play on OPpvp much.
That's allowed. The person was just annoyed probably that you kept killing him. (That's what I think)
That is not what he is saying, There is a command alias for /spawnmob or mob, that allows unlimited spawning with no cool down.