It's such a joke on this forum, how some people assume that, whatever their opinion is, the opinion of 'liberals' or 'greenies' must be the opposite -- when actually they agree! It looks like a desperate attempt to manufacture conflict and division.
The most liberal cities in the US have modified their building codes to allow greywater from S&B houses to be drained directly onto the ground, or into holding tanks as another poster described. These ordinances vary in their details, as they should, due to local climate conditions and health concerns. Less liberal municipalities will follow suit.
Personally, if I wanted to dump a grey tank in a park I would ask park management. They should know what works in their particular environment and what doesn't.
I did once rinse vegetables in a bucket and dump the bucket in the bushes next to my site at a low-rent urban RV park. No soap. Was this bad? Maybe I should ask staff first, next time.
PS: AS for toxicity, greywater from showers and laundry does contain E. coli (you can google the science). And of course water from the kitchen sink contains bits of food that are old enough to give you food poisoning. Don't drink grey water or eat yellow snow. But do rely on nature to detoxify both over time.