Two things I can think of: first, that the harvesting process will unavoidably involve killing a lot of lac bugs, even if they’re filtered out later, and secondly, that some vegans include insect-produced substances (notably honey) in the things they avoid.
Also addressed in the video! Neither I nor the video creator has any stake in what you choose to do, and I’d prefer not to rehash the whole video for you since it’s right there for you to watch if you’re interested in this topic, but the main points were generally about reducing subscription costs and gaining better control of content (e.g. no surprise removals of music, videos, and ebooks).
Persist with the video! The text-to-speech is only for a couple of quick screens - the rest is very personal, and they cover a bunch of use cases.
If you really don’t want to, the server OS they recommend around two-thirds of the way through is YunoHost, a beginner-friendly way to run services as containers on any capable spare computer. The YunoHost website has a bunch of use cases that are also covered in the video.
Link for mobile accessibility: https://libredirect.github.io/index.html