@Mark Manship a neighborhood is a community. A street filled with vacationers is not a community. You are looking for a smoking gun as to why STR are evil and that is not the point anyone is trying to make.
Quality of a neighborhood is more than schools and crime. It is relationships and neighbors helping neighbors. A good neighborhood lifts itself up as more neighbors improve their properties. It is a place where kids can play with other kids. A place where you borrow a tool from your neighbor and they get your mail when you are on vacation. A place where you know which car belongs to which house. People drive slowly because they respect their neighbors and there is accountability because people know who you are and where you live. You mow your lawn because you don't want the neighbors to think you are a loser. People plant flowers and water them daily. Neighbors warn neighbors of dangers and look out for each other. Simply put, nobody wants random people continually moving in and out of their neighborhood.
All communities have standards for property owners that limit many aspects of use. The purpose is to maintain the quality of the community, so that it is an appealing place to live. In my community, you have to keep your grass mowed to 8 inches. There is restrictions on how close to the property line you can build. My neighborhood has limits to the type of fences you can build. We can't store piles of junk outside. We have restrictions on tree planting. The list is long and it limits what a property owner can do. Does it interfere with my property rights? Yes from the standpoint, I can't do whatever want. That is a good thing, because people left to their own choices, often make bad choices.
You may believe having transient neighbors cycling through who have no community knowledge or community connection is good. Maybe you prefer your neighbor to be a stranger in a strange land, but the overwhelming majority don't see it that way.
The idea of unchecked and unlimited property owner rights sounds good in theory but fails in practice.
As far as occupancy standards. This has two logical purposes, safety of occupants and limiting the demands on city services:
1. Fire safety is the first reason that occupancy standards where enacted. There is many cases of people dying trying to get out of a property. Long term rentals are subject to occupancy standards. Hotels are subject to occupancy standards. A STR is somewhere in between, so it is is completely logical that the same protections should apply to STR properties.
2. As far as burden on city systems, the maximum unrelated adult occupancy rules aim to reduce street parking demands, control traffic and keep water/sewer systems from being overloaded.
You want to compare owner occupied to a business renting the property, but they are totally different. The rules are always different for ANY business. If I am cooking food for sale, the rules are different than cooking for my family. I can have 15 kids of my own, but if I am watching other peoples kids, I am subject to daycare rules and limitations. The difference is when businesses are left unregulated, they make decisions based only on profit. What is more profitable is often not best for customers or the community. Bad actors exist in all businesses and STR is no different. (It may even be worse because of the low barrier to entry).
I wish everyone just naturally did the right thing, but they don't. And more importantly everyone has different views of what is right. That is why we have laws and ordinances. These are common guidelines we can all follow.
I would caution you that when you push the "all or nothing" mentality on any issue, it has a tendency to make people snap back with the response of "fine then nothing". In other words if STR owners fight any regulation to the death, it can have the opposite effect of creating a stronger lobby against them. It is much better to say, yes we agree to XYZ standard but maybe modifying it to 123 instead of 456 would be more reasonable.
Of course every city is different. What may work in one city may not work in another. Some cities over regulate and drive people away. Some under regulate and drive people away. You can lobby in your own city and shape the destiny.
