He is talking about lag, PING and LATENCY aren't controlled my computer speed, that would be FPS. Your best bet is to just play on european servers. The servers are in the states, so your speed will drop quite a bit, but if you were trying to say "On other servers my ping is fine but on PB it's horrible" Well, than we have noooo idea.
Great for a finishing kill. You saw your friend knife that guard, and your bud got owned. You want revenge, charge widly, and hit you "V" buttom (Most people have it bound to V)
Profit.
He didn't listen to a CT's command. It was a grenade, it can be used to hurt and kill the CT's. I don't believe it was a freekill. He got warning, and according to you, many warnings. There is no planting of grenades (I think?) so there is no "He wasn't paying attention". Straight up legit "You didn't follow orders" Kill.