I wrote an earlier posting responding to “mdd” but it was ignored so let me answer him briefly. Actually, “yitaiy….” has done a masteful job in showing sources whether uncovered hair is d’oraisa. Thanks, especially for the “terumas Hadeshen’ that I did not know.
I wanted to respond to “mdd’ question whether I would be ‘dan lekaf zechus” for the “ovdei avodah zoroh” of bayis rishon? Actually, “mdd’, yes, I would be ‘melamed zechus” on any jew, regardless of the sin. This is how Moshe rabbeinu conducted himself, how the nevi’im acted and how all our gedolim went about for centuries. You should remonstrate them (hochocho) but, in the final analysis, you must be a “senegoir” an advocate for any Jew.