Timing is important to protecting your buffs. When your mid is getting caught out as they're heading to blue you fucked up. I dunno what else to say. They have to be in place and ready to take it, and there was another time where Nautilus sat on his smite even with Shyvana around because he wanted Ahri to take it.
Timing is important, but at 7mins, shen was already much stronger than wukong and so if they contested it, they'd very likely lose
So gank the lane before there's time for him to get so far behind. You have to be some kind of threat to top.
Shen doesn't even need to be ahead to escape ganks so easily though. Dash and shield, bye bye. Wukong needs his 6 before he could support the gank and by then shen was pretty ahead
I get the pressure. Why commit to fights if you know Shen can go in then? Getting baited and pretending like you didn't realize Shen was in the game is just poor play. It's a long cooldown, that can be taken advantage of and there's no reason you shouldn't be able to push a lane while he's out. Shen is a good champion, but the idea that he is unbeatable and is overpowered just seems like a defeatist and rather lazy attitude. Look at Hotshot not even wanting to lane against Yorick.
As I said, never fighting your opponent means you've already lost. I wasn't saying it was impossible for wukong to push the lane when shen is gone, just that it would take very long - since he was at his tower initially.