The problem here is that the Palestine people aren’t being given control of their water.

Yeah there are good reasons to limit or prevent rainwater collection in order to preserve necessary river systems or agricultural areas etc.

However I highly highly doubt anything good faith is going on here.

The context is very straightfoward. It is an occupied territory. The occupier claims ownership of natural ressources in the occupied territory. This is typical imperialist behaviour and illegal under international law.

https://youtu.be/QZkSRlIs9o0?si=l7jYk8g92oIS4t3b

The evil part is having laws like this and then filling in their water sources with concrete.

To add what others said (like Israel making up rules for Palestine), the people of Palestine are being attacked and their infrastructure targeted. It is pretty evil to destroy the water supply and then say: "but you can't get it elsewhere :)".
I don't think this is necessarily the case here, but laws like this are often an attempt to offer the appearance of legitimacy to acts of violence (i.e. "yes we imprisoned them but they broke the law!").

and who better to claim ownership over the rain falling on palastinian soil than the israeli government

i dont think you can justify this stuff, at best make it sound slightly less evil

Water for agricultural and domnestic use usually is fed back to the water cycle, though.

Watering my veggies is distinct from e.g. building a dam, or something.

AFAIK, there is no such laws in Europe. I know for parts of USA and Israel. Correct me if I am wrong.

There are laws about collection and storage of rainwater all over the world unrelated to genocide.

I never seen them before. Too much rainwater is a problem, but not collecting it.

Oh I think it’s meant to be just as evil as it looks.

It makes more sense to limit the amount of water collected than to outright banning it tho.