It seems that stock clients can only go up to 732kb blocks. Miners/pools need to manually raise this limit, and that's what some did... While others have the limit on stock settings.
OK, thank for this technical answer.
and this guys want to raise the block to 8Mb ... ? they don't understand the basic setting of the actually stock client ... 
Yes, apparently they do. They don't need to understand the "basic settings of the stock client" to raise the limit to (or close to) 8MB
Last time we checked the GPS, we are also in China.
Exactly, so it's easy to conclude that this doesn't fit you
So if we have 8 MB blocks what is stopping miners to manually cap their blocks to 732kb ?
Nothing. But if they don't change the settings to raise the limit, they probably won't change the settings to decrease the limit
