> Do you mean "the GUI shows 0-conf transactions as pending?
It's not just GUI but also a miner policy which can break the use of BTC as cash - as it was originally intended.
> And why does adding Segwit make it "not bitcoin anymore"?
It's an ugly addition to the original protocol that among others breaks the definition of a coin as a chain of digital signatures. This might lead to legal issues as some people (including lawyers) pointed out.