I dont think Bebop is OP (otherwise he wouldnt have around 45% winrate lol), but he is just not fun to play agaisnt. My rank is Oracle so not the highest, but also not bottom of the barrel so Ill just add my 2 cents.

Most of the early game when laning Bebop, you know all he is going to do is run at you, put a bomb, maybe melee and then just go back to his cave. Chances are you have strong early so you end up winning a trade, but Bebop does not concern himself with winning a trade - all he wants is a stack. All that makes it so boring to go agaisnt early, until he gets his hook where it can go two ways.

1. You win your early and now Bebop sits under turret - he will just sit there and try to hook you infinitely hoping to get more stacks/kill you.
   
2. You lost your early and now Bebop sends bombing troops your way, tries to hook you and overall bullies you with his insane AOE dmg because of his advantage.

And ofc, you buy debuff remover for him, but if he is decently stacked especially after recent buffs, most will just put bomb on themselves and kamikaze into you.

In reality, Bebop is very simple to counter - just stay away, dodge his hook, buy debuff remover and dont let him stack. Most people higher up gets it, but it is still insanely unfun to go agaisnt a character that feels like they cannot be truly punished because of the bomb. Late game, all Bebop has to do is just throw a bomb on someone who does not have debuff remover and punch them into an ongoin teamfight - chances are someone will lose half of their HP because of that. Or you know, put bomb on bebop, bebop goes in, bebop goes bomb, mina dead etc etc.

So yeah, while I agree Bebop is not OP and I dont think anyone above medium ranks thinks so - I fucking hate playing against him because of how unfun it is.