Animal products are all across our civilization, regardless you use it personally or not.

Horseshoe crab blood is used to perform specialized tests and analizys. Many forms of gelatin extracted from animal tissues is used to inoculate cultures. Ever heard of lab mice and their importance for scientific research and development, especially when it comes to biomedical and pharmaceuticals? Are you aware that pigs provided human compatible insulin for decades before the synthetic formula was developed? You know replacement heart valves can be harvested from animals? Horses aid in producing antivenoms.

These are very niche yet very important roles animals play to support our entire civilization.

So enjoy your dietary option and allow others to do the same.