Who said anything about building up their forces? All I mentioned was reconstruction of the region e.g. all the homes, businesses, buildings etc that have been utterly demolished get rebuilt, that those who have been forcibly displaced are allowed back, that basic humanitarian aid is allowed and that hostages and prisoners are given back. I haven't said anything about 'Hamas forces'. There are also other factions that exist outside of Hamas, by the way.
There's nothing unreasonable about any of this and the only reason why it won't happen is because Israel doesn't want it to. If these terms are seen as 'unacceptable to Israel', then that tells you all it needs to about them.
Israel's resources vastly exceeds anything Hamas could ever do, too. So even if Hamas were to 'build up their forces', Israel have more than enough artillery and tech to keep them at bay. So I don't see this as a valid reason.
Mentioned it ages ago on this thread, but you'll see lucrative deals for friends of Israel and the US to 'rebuild' Gaza.
None of it will be of benefit for Palestinians though.

