Why is this a thing (Jhin)

Because he's fed and his team is ahead. It's 7 towers + Baron+ First Dragon against a team with 3 towers and unknown number of dragons. The other team's Jhin is no where near that point.

not sure what you're talking about the AD? I got 947 on my Jhin

it's messed up

I feel like riot has been making their champions very balanced lately. This is a very good example

I dont get it.

He might hit u like a truck but remember he loses to literally every adc in a 1v1, since he can only hit 4 times very slow....while others hit u 2 times in one second and 5 in the case of ....and also he is kinda like a sniper so yea, they hit like a truck...