If BSD isn't open source then I don't know what is.
> I mean they're definitely free but have you ever tried submitting a patch for something that doesn't matter to FB/Google?
Well, you can always fork.
> Those projects function as free bug finding programs for their respective sponsors.
Yes, most companies engage with OSS strategically and not purely altruistically. But also:
1. Big tech uses OSS.
2. Big tech does not have internal versions of many OSS projects.
3. Big tech uses OSS for reasons other than just recruiting.