Because it's not good for the game.
Even without rhe 2xXP weekends, it's already way too easy to level in this game and there's really too many people that reach 50 without understanding how to play PvE in a group or do warzones. The more you simplifie leveling, the less people understand their class, their role and how to behave in a group.
I don't even use the power level technique but this post is just pure bullocks.
The whole "people need to sweat, bleed and stumble" their way to 50 is just a talking point people use to feel special. It's just like when people complain about how hard they had it but no one else has to hard. The more 50s the game has the better we all are.
The leveling process does very little to force ANYONE to understand their class. Need I remind you the leveling process does NOT force you to group. It does NOT force you into flashpoints and it does NOT force anyone to play their class "properly".
The whole, "I want to feel special because I'm 50" attitude needs to end.