I dunno, ask them.

Hamas Member of Parliament Khalil al-Hayya, also deputy chairman of the Hamas Political Bureau, told the Associated Press in April 2024 that Hamas is willing to agree to a truce of five years or more with Israel and that it would lay down its weapons and convert into a political party if an independent Palestinian state is established along pre-1967 borders.

More seriously, Hamas’s claim to legitimacy is their fight for Palestinian self-determination. If that’s back on the table, they won’t be able to maintain their authoritarian state anymore, because both Palestinians and the international community will want them gone, or at least out of power so democratic elections can take place. Also, this is pretty much what they accepted in the Jan 2025 ceasefire; it’d be a political impossibility for them to maintain undemocratic rule without active Israeli aggression and they know that.

TL;DR: Because they’ll have no other choice. Also I’m not sure what this has to do with my comment.