Lunatics like these can't be sated by the official songs: https://youtu.be/CKwX349aV98 https://youtu.be/sJQSy3KG-oQ?t=33
That first chart averages 12 notes per second for 5 straight minutes and the player only missed a single note.
1. On that note - my tremor does hurt me here too but unlike twitch shooters (which I loved before my tremor got bad) and things like guitar hero (which require comparatively precise movement) beat saber is usually pretty forgiving about precision of placement and angles - so long as your rhythm is correct you can go pretty far with it.
OG BeatSaber comes with a small-ish selection of tracks, most of them obscure and not generally known. Good or bad, they get boring quickly. Modding lets you expand to arbitrary number of tracks, including pretty much all the ones you like. It's what makes it fun and worth returning to. Not being able to add your own music, makes BeatSaber not worth the sticker price (much less if you're getting Oculus just to play it).
Also note that people were used to this capability, because before BeatSaber became a poster child for Oculus, it was streamed to other headsets from PC, where adding custom tracks was tacitly allowed.
There's moral discussions to be had I'm sure, but the purpose of the beat sabre mods is pretty factual :).
This is especially true within the rhythm game community, for which many fans simply like to make rhythm songs and for people to play them.
That is absolutely a valid usecase that should be allowed.