Yes, the parent does have a responsibility here also, but so does society. This has never not been true.

Society perhaps. But schools? I acknowledge that this has become a task shoved off onto schools, but I do not think it is appropriate to schools. I think that a difference of opinion here, on this issue, is actually one of the fundamental points on which those who favor homeschooling and those who not will diverge.

I also disagree that this:

You absolutely will be thrown into uncertain social waters in your work place in which you will have to navigate a broad spectrum of personalities is prepared for by this: You learn to deal with these complex social variances via proctored interaction with your classmates as overseen by the teacher

That rightly seems to me to be task of a "finishing school", rather than one of the sorts of general education institutions we have now.

If the teacher is actually, actively teaching "social skills", then this comes at the expense of some other subject. Time is limited, after all. Teachers have only so much; so do students. If "social skills" are not being actively taught as a subject, then this appears to be no more than learning how to get along with others, which is something families should already be practice for.