My point is that you made the implication that because of how gelatin is produced or sourced that it's not appealing to you.
Gelatin is made from collagen that comes from the same animals (pigs and cows, not horses) that are used for any number of other foods and edible products.
Commercial production of gelatin doesn't use hooves as they are not really the best source where bones and hydes are. Simple economics here.
Hamburger meat is ground beef, which is steak in a different form. In and of itself, hamburger is whole food and in the context of building muscle and a reasonably cheap form of protein, it is certainly a 'healthy' food like any other whole source of protein.
Pork rinds are fried skins. For some who choose a low/zero carb lifestyle, they are certainly within reason to eat as a snack and source of fat. No, someone would not make them a staple of any diet, but they're not the horror folks make them out to be in the right context or in the right diet.
There are liquid amino acid products available made from 'gelatin' (I won't name the product that I use out of respect for Biotest). It even smells like gelatin. It delivers a shitton of protein.
You can't just assume 'fish oil' in and of itself is 'healthy'. Too much of it is not good for some people. Unless certified, there is the chance of heavy metal contamination. Ever see a fish processing plant? Not too much different than any other 'meat' processing plant, and they use every part of the fish for 'stuff' as well.