That's not true at all. I love deception for example. Alot it's one of the first specs I've ever played (the very very first was madness sorc, then deception sin, then Marksmanship sniper). But I loved it when it was either balanced or slightly underpowered. It doesn't feel the same when it's OP or when it's severely nerfed it actually becomes a bit discouraging to play in those scenarios. It's not that I don't like the class it's I don't like it being overtuned/undertuned. (Also before someone jumps on my deception just needs bugs fixed to be balanced it's just these aren't funny bugs like lol slash constantly hitting).
Some people just don't like playing overpowered classes even if they enjoy the class. That's all there is to it.