I think its because most people forget the whole "Overall M+ damage" about the argument
Ignoring the argument about that if the OP is talking about the "feeling" then i dont think how anyone cant agree...
I mean you pop everything and vaporize trash on a Fortfied 15+ dungeon and the next pack you rotation,rotation, WW, rampage, rotation rotation..woo!
And then you log onto your DH alt without even proper legendaries and simply because the spec at its certain form is how it is, its the same on every pack pretty much, which is simply fun.
Same with the DK and i am pretty sure WW monk is the same, and a couple others.
There are simply some classes that are more "fun" when it comes to M+ and the majority that doesnt know what they are talking about would obviously focus on that.
Obviously the overall damage of the dungeon and the uptimes do not change, the argument is silly to focus on that..but the playstyle fun is a very relevant subject