Jamal already kind of covered this line of thinking, but I'll address it from another vein. Good hate control doesn't exist at low levels. Ninja flat out sucks before Utsusemi: Ni. Don't act like you're gaining really valuable experience when you have almost nothing to do your job properly. Most job-defining abilities/spells come in the 30's; before then you're no where close to that level of effectiveness. If you can blaze through those shit levels(especially 1-10, where you're not even partying) and get to a point where you can actually do your job properly all because of a PL, good for you.
As far as skills go, it's not like you can't get them a little later and you're also not going to be power leveled your entire career. Even if you're a tank, you're going to be trying to hold hate as long as you can until the PL pulls hate; and they don't even do that on a lot of fights. That really only pertains to actual skills in the game, in regards to learning how to play, this game is not remotely difficult to learn. As long as your head isn't up your ass and you can pay attention, you can do any job in the game better than at least half the people out there(who cannot do one or the other, sometimes both).
It is personal arrogance to try to deny a group a power level just because you personally don't like it. If you're against it, leave, but don't fuck over 5 other people just because you don't like power levels. Personally, I usually enjoy having a power level at low levels. I've leveled more than enough jobs to know what I'm doing and I have better things to do than to get shitty exp. A power leveler gets me through those crappy low levels faster, with much less hassle and expense on my part; I don't see any problem with it.
There's also nothing stopping a group from being power leveled and using strategy at the same time. Maybe you've only partied with brain dead idiots when you've been PL'd, but I've done skillchains + MB, had the tank voking the whole time, and had the blm's play intelligently all while under the watchful guidance of a 75 whm.
He's either a bot, or he's just retarded, a PL has nothing to do with that.