OK.... here we go....
Have you considered what wildlife does when it has to go potti? I can assure you that they don't hold it until they are away from the water. If your sailboat can produce as much urine in a year as one whale in one shot, I'd be mighty impressed. Backyard pool doesn't even fit into the same category as a natural ecosystem that both feeds on the nutrients, and is HUGE in comparison.
Are you aware of what sewage plant effluent contains? Look it up, I'm not a teacher, and I'm sure you're old enough to look into the stats for your own municipality.
Either you spout rhetoric based on xenophobic opinion, or you get the facts and you don't. - Science.
I'm sorry, but the first 2 paragraphs and the last one are in sharp contrast. Each side of the debate seems equally able to select only useful arguments. and reduce counter arguments to the absurd.
Perhaps a few links would be interesting. I'm not saying what these add up to; my opinion is mixed and not set.
EPA fact sheet.
An interesting early attempt.
Henry Moule - Wikipedia, the free encyclopedia
The don't seem to be many NSF approved devices. But I haven't researched this.
NSF Certified Products - Wastewater Treatment Units and Related Products, components and Materials
Excel Composting Toilet by Sun-Mar
Do Air Head or Nature's Head have any EPA or NSF approvals? I didn't see them on the web sites. Based on the other reading and their size, I'm fairly sure they would fail and so have not tried.
Type 1 MSDS have been subjected to NSF testing and approval. However, since they are discharging into the water, this is a different thing. Do remember, however, that since the influent is ~20x more concentrated than normal POTW influent (as determined by BOD5--no shower or flushing water) that the results should be divided by 20x.
NIH evaluation of dry heads.
Survival of Fecal Coliforms in Dry-Composting Toilets
Clearly septic tank waste and diapers are allowed in landfills.
So, there is some science and some regulations. I seems to me that the non-MSD boat heads fall in the gaps somewhere; a regulator is going to see them as porta-potties I guess, since they neither discharge nor compost (to NSF standards). They simply dump solids rather than liquids. Real and perceived health and environmental hazards vary with the disposal in both cases, and are minimal--too small to fight over--in either case if managed well. As for mismanagement (over the side, mate, or just throw that under the bushes), well, that's just fight territory.