What's the difference between the honey created by bees and the nuclear waste of a nuclear reactor?
If you get rid of the pro-not-human narrative there is none.
Plastic is another unbelievably horrible man made concoction which is absolutely destroying the natural world due to poor handling.
Since plastic waste and nuclear waste aren't food for other organisms, or don't naturally break down, they're not materials that belong in the natural environment. The is the same environment from which you come from, owe everything too, and which you're still totally and utterly dependent on for your survival.
Hopefully that's a good answer...
By the way, I used to share your beliefs, that it's all the same, it's all "natural", but I just can't keep up the mental charades anymore. Our intellect and creativity is an important part of our short-term survival, but thus far it's been massively destructive and I can't see that changing anytime soon.