Generic topic. Ultimately it is never correct to flame and harass a teammate. That's a given. Anyone who disagrees with this very statement is likely to be an a-hole.
HOWEVER, there are circumstances where the jungler practically trolls a lane by not ganking. If the enemy jungler is hard camping a lane, the team jungler really should at least consider a counter gank when near, and pressuring other lanes/objectives when not near. To see your own jungler at the nearest camp just AFK-farming while you are being tower dived is absolutely infuriating and borderline trolling/griefing.
I'm a top laner/jungler so I see both sides of this argument. Again the bottom line is flame/harassment is always wrong regardless of the situation, but there are times when the jungler does boderline troll by not even consider helping (even when they know where the enemy jungler is). Likewise we often see laners going AFK because they gave up for no good reason.
Only 5 or 6 games ago I practically played 2v1 top lane for the first 12 mins. Luckily that was a game where I played my best and ended up going 15/1 and carrying the game. However, not once did my jungler gank, ward, help, communicate or even consider pressuring the map elsewhere while I was getting perma camped. And that, for me was OK. What wasn't OK was that the jungler went to my lane on 2 occasions when I backed, to clear full waves. That is griefing.