To be honest - the Survival Games are the only place I've ever seen block-hitting despised, I can find many other servers were they believe people who don't block-hit are noobs.
Example:
www.youtube.com/watch?v=hz5kbWnE81Q&list=UU6HHPQhGfduAV8yMMGtktSA&index=6
In my opinion block-hitting should always be done where necessary - it's just that you're not doing it right.
It actually takes skill to do so because you cannot swing whilst blocking, so you must time it right by swinging then immediately (within milliseconds) block and repeat whilst fighting. It's very hard to keep consistency when doing so. You can still block-hit slower, and spamming it... but you'll have less momentum and you'll get less hits in then you would if you did it consistently or normally swinging. Blocking hitting gives you an advantage, yes, but it takes skill to do it good.
Unfair advantage... wut. That's like saying somebody with a bow has an unfair advantage, somebody with a golden apple or within other games there is a fine example of players cussing out others because of their weapon choices as shotguns, etc. It's been put into the game for a reason besides making silent truces...
No offense to anyone, but in my opinion anyone who believes block-hitting is unfair, stupid or always takes no skill at all is stupid, they are bad - and they should feel bad.
Ohh no, ders a player who is using something that the game has to offer for an advantage and I don't want to use because it makes me feel less skillful so I'm just going to hate and point them out.
TL;DR: Balloons.