...should we buy it?
nothing named B2X exists for you to buy it or not. there is only a future market in bitfinex which is best that you stay away from it.
Because as I read, if there's no replay protection, so for every B2X dumped, there will be a equal number of BTC dumped. If someone sell one B2X, they will be selling one BTC to the same recipient.
then you are reading false information or maybe interpreting it wrong.
as i said there is no B2X to have or don't have replay protection, so all the arguments about it is pointless.
and even if it didn't have when it was released, then it wouldn't have anything to do with "Dumping" you dump on the exchange and buy it there, and for that there is no BTC to be dumped, you bought B2X after the fork.
what they say about replay protection is that if there were none and you spend coins on one chain and the same transaction will be valid on the other chain. for that you have to have bitcoin before the fork and also you have to spend it.
SegWit2x already has an Opt In replay protection by the way, and when they release they may even add a strong one or it may even die before being released.