Yes, but that doesn't mean it is decentralized. In fact, centralization of mining power is one of the biggest concerns for BTC now. Further, I don't think BTC protocol allows rollbacks.
It's decentralized if no one entity has 51% power (or 90% when TF is implemented in a few months). There is no one entity in NXT that has 51% forging power. If forgers decide to download the modified release and do the rollback, then it's democracy in PoS style. BTC software could also be modified to do a rollback and if enough miners download it and reach 51% of mining power OR if enough miners decide to secretly mine a separate chain and reach 51% of mining power, they orphan all the other miners' blocks.
For some strange reason, you seem to equate the majority threshold and democracy as the benchmark for decentralization.
It is not.
Further, don't keep snipping our conversations. Otherwise, I might forget you earlier claims such as BTC has done rollbacks before.
Also, your last two sentences seem to refer to forking.
I hate overquoting.
I think I stated clearly what centralization is - one entity holding 51% of the mining/forging power. This is not the case for NXT.
Yes, my last sentences refer to forking. So what's your question?