While I'm not top talent, and haven't been pursued by Facebook, I've always wondered why anyone would want to be associated with them. Other than as a status symbol in tech. I've never thought of them as anything less than a reprehensible company.
If your career goal is to set yourself up as a PHP guru, some FB credentials could be useful. If you think about it, a guy who wouldn't mind his career being about PHP is exactly the type who wouldn't get why ('zuckerberg-couldn't-get-laid(a-busines-carries-founder-DNA)).
I also remember a time when FB was seen as cool compared to MySpace, because it hinted a higher social value because you supposedly needed to be an Ivy league student to have one.
I don't see how the opinion you're promoting here is any more mature than what you're criticizing.
My explanation is relying heavily on a sociological observation. I don't see how that is immature.
Let me put it another way.
People who tend to not to value specific elements of fashion and style, do so for many reasons, one of them being that the subtler elements of these matters elude them. Or if they catch them, the do not pose high value on them.
This is what also predisposes to be comfortable with life choices that completely ignore certain elements of fashion and style. One example of such a life choice would be to make PHP the cornerstone of your career.
As an adjacent point, I think the same reasoning can be applied to professional-cultural disparities in general. Such as my gradual distancing from swathes of career software developers in that I'm no longer able to construct a scenario where I wouldn't care about things like well-being, culture, why and what I'm putting out into the world.