If this were true you would see a lawsuit based on Leahy law in the states. The fact is it's just not. Israel has held aid occasionally but most of the problem with supplies have to do with Hamas stealing them.

https://www.state.gov/key-topics-bureau-of-democracy-human-r...

I don't support a lot of the stuff Israel is doing but painting it in this light is deeply incorrect and unfortunately hurts Palestinians. Both sides escalate and the result of such escalations are always worse for the weaker side.