Sorry, I live in the adult world, where you have to have a job, to pay rent, and you know, live. Most of the people on this site who are creating new sites are in their teens, and are creating it while they're at school, doing other things, etc. I've been there, and I'm one of the very few people in this entire community who was able to pivot and turn it into a real job, that has given me something I can call a career.
What I'm saying is that the majority of sites that you see on this forum are hobbies by the owner. Who are they going to give it to? Other people who are going to consider it a hobby. I think that telling someone what to do with their property (as the owners of these sites have the right to do whatever they want with them, including completely ignore them and let them die) is incredibly entitled.
I think what you're doing is taking what I'm saying and twisting it. I have websites that I consider hobbies. Most of them are still somehow bigger than all of the sites on this forum. I'm able to dedicate time and energy (and resources) to them because I have a real job that pays the bills, and gives me the free time to work on other things. That is my main point. The amount of time and dedication required to make a successful pet site (in terms of features, or just in terms of having it work) can be extraordinary to be doing it for free, or very little money. I know that some people do it because it brings them great joy and passion, but that only lasts so long when you're up at 3am answering bug reports or fixing servers. The majority of people quit because they come to realize that they're spending hours a day doing something that is unpaid, and is not furthering themselves in life.
I personally only do things that are worth my time, and working for free under harsh circumstances (as working on the internet usually is, like I said above, people are incredibly entitled and feel like they can dictate everything you do) is not one of them.
Whoops, super long post.
TLDR; It's appropriate for pet sites to be hobbies for most young (And adult) owners because it is not a real job for most of them, and dedicating hours a day to something you are getting nothing from is insane.