Here's the thing, if FB really wanted to do the 'courtside seats' thing, they should have licensed being able to stream the feeds through the FB web site - In terms of revenue stream, they'd make a boatload more $$ off of charging for that than they will by attaching it to a $1500 piece of headgear that you're not going get away with slipping on in your office to sneak a quick game.
The point is that to stream video from an NBA game you need to license it (you can't even carry pro photo gear into a professional sports venue without the appropriate credentials, let alone hook it up to the internet and stream video out of it). So this is totally pie-in-the-sky above and beyond the technical side of it which is perfectly feasible with off-the-shelf stuff today (Occulus would simply be a nicer HMD than most).
The NBA has heard of Facebook. The NBA probably had not heard of Occulus. They certainly have now. These are the kind of things that once the technology has matured a bit the Facebook association will really help out with.
The idea that brands like NBA/MLB/NFL won't want to get in on selling people VIP VR Experiences is crazy. VR is going to be absolutely huge, it's the next truly disruptive technology.
I don't think Facebook would necessarily "ruin" Occulus (although it likely will) but I don't really see the fit. Courtside seats at basketball games -- OK totally doable technically speaking, but the hard part would be licensing.
If VR ever takes off in the mainstream it will probably end up becoming a "FRAND" kind of deal, where a bunch of key players pool their patents. Occulus will be a player, but hardly the only player.
I could see Sony or Microsoft wanting to sew up Occulus (although I think it would be a mistake to sell to either). Facebook just doesn't make much sense. Maybe it's just Zuckerberg really likes the technology.