What people are trying to get at, I think, is that if western states like the UK recognise Palestine as a state, it limits the kinds of actions they can take toward Hamas.
It's not about what Hamas thinks about any of it. It's that it's considered a big deal, even an act of war, to attempt to remove the government of another nation, whether or not they are good or evil or even if they are some kind of dictatorship.
Right now the status of Hamas doesn't protect them in that way, but if they are the official government.
Setting a precedent of simply removing a government they don't like doesn't look good, and they likely don't want to be in a position where they are now at war with a legitimate governing body of a state. It's not likely that desirable even to say, we recognise you as a state, but we won't negotiate with your government.
Or to put it another way, it doesn't do much good for Palestinians to recognise them as a state, and immediately they become a rogue state without normal international relations, or even at war with other states. They would be terribly isolated.
It could also make it less likely that some other group could arise and replace Hamas.
The fact is that as long as Hamas is there, it's going to be very difficult for any real change or progress to happen in Gaza, and that's not just because of Israel, nor because they have no interest in doing anything good for the people of Gaza, it's because no other moderate nation, including the Arab moderate nations, wants to have anything to do with them.