I can provide a little perspective since I started my career here as an FA. And let me preface with saying I wholeheartedly agree there is a shift in abusing the whole "it's bumpy, I don't feel safe doing service" thing. There's an unfortunate amount of people that just wanna sit around and do nothing.

That said, it's not necessarily that the bumps are "worse" in the back (although, speed brakes will make your teeth rattle off your face in the aft galley), it's how the bumps affect the carts.
Galley carts are skinny and top heavy. Now load that cart with water bottles, coffee and hot water carafes and snacks and you've got a very wobbly and very heavy Jenga tower.

Personally, I had no issues doing service in bumpy air. But occasional moderate chop or constant light can still be a challenge when it comes to pouring hot liquids and that very vulnerable instant when you're reaching passing a drink to the furthest passenger by the window. The wrong bump and you're tripping over someone and/or spilling on someone's lap. Also, chop during service slows you down so damn much between trying to slowly pour drinks and trying to do things while keeping one hand on the cart to keep it from wobbling like a dealership tube man.