The USA doesn’t give money or arms to Hamas, but the USA does give humanitarian aid to the People there in Gaza through agencies, such as UNRWA who administers the programs.
And Israel, who controls the goods that go into Gaza (they have a blockade around Gaza) does let the goods that the USA sends in through UNRWA go through their checkpoints, as Israel has no problem with that.
What Israel doesn’t let go through their checkpoints or past their blockade are arms and material for war going to Hamas.
I hope that now that Israel has cut the gordian knot and is likely to press on to obliterate Hamas, that the US will stop its illegal funding of Hamas through multiple grants including its funding of the Palestinian Authority and the $47 million that John Kerry committed to them this week.