It goes back to 17th-century Lithuania/Russia (maybe a century or two earlier).
It goes back as far as we (collectively) remember.
And R’ Schachter doesn’t say that the issue is a meta-Halachic concern.
I suppose that depends on how to define “meta-halachic”, but my point is that it is a matter which requires judgment which is beyond the typical debate you’ll find in a beis medrash. I agree that the judgment of morei hora’ah is part of the actual halachic process, it’s just hard to qualify precisely, as it is to determine which morei hora’ah are qualified to make such judgments.