This is what I did as I had deleted my Facebook account years ago. I haven't run into any issues so far and it's been working with my Oculus.
Currently there is no reason to believe that Facebook should be trusted for anything (based on their past actions) or that the current regulatory environment (both US and EU) is effective at discouraging and punishing violations.
Wasn't this part of the settlement with the FTC for about 5 billion dollars? I'll agree with you it evidently is not enough to really deter Facebook but I wouldn'T call it nothing, that was one of the largest fines ever handed out.
Same in Europe, Google has taken significant fines. Those companies are not untouchable any more. And yeah I don't trust facebook that much either but I don't think they'll blatantly ignore the law intentionally.
Also don't forget that there is quite a social factor to VR and they are pretty much going in the "single player only usage without FB account direction".