We’ve made dams long before we knew about electricity. At which point tacking hydropower to a dam that would exist either way has basically zero environmental impact.
Pure hydropower dams definitely do have significant environmental impact.
I just don't get the premise of your argument. Are you honestly saying that stopping the normal flow of water has no negative impact on the ecosystem? What about the area behind the dam that is now flooded? What about the area in front of the dam where there is now no way to traverse back up stream?
Maybe your just okay and willing to accept that kind of change. That's fine, just as some people are okay with the risk of nuclear, the use of land for solar/wind. But to just flat out deny that it has impact is just dishonest discourse at best
It’s the same premise as rooftop solar. You’re building a home anyway so adding solar panels to the roof isn’t destroying pristine habitat.
People build dams for many reasons not just electricity.
Having a reserve of rainwater is a big deal in California, Texas, etc. Letting millions of cubic meters more water flow into the ocean would make the water problems much worse in much of the world. Flood control is similarly a serious concern. Blaming 100% of the issues from dams on Hydropower is silly if outlawing hydropower isn’t going to remove those dams.
Pure hydropower dams definitely do have significant environmental impact.