Facebook pretends this is the case, but they use some dirty tricks to require personal information without explicitly requiring it.
In particular, if you create an account without a phone number, you'll find that within a day or two your account will inevitably be flagged for "suspicious" behavior, and you'll be required to enable two-factor-authentication with a valid phone number. (I assume the "suspicious" behavior here is your account existing without a phone number.)
I've seen this pattern and the excuses people make for it too (anti spam prevention, as if there are no other anti spam prevention methods)
How would I remain as anonymous as I am on Steam for the community and still work within Facebook's terms of service?
Use Firefox, it automatically puts Facebook in its own Firefox Container so no FB cookies tracking you everywhere. And don't use their app it's basically spyware.
If you are only using the FB account on your Oculus, its an Oculus account that calls itself an FB account. You need an account for most game devices these days and for Steam. I am not saying its perfect, I am saying that not using an Oculus because you are off FB doesn't make that much sense to me. I do exactly that.