His point is that it's offensive to prejudge all men in tech as incapable or unwilling to treat women as equal individuals. This sentiment is rooted in the idea that most men are not sexist, chauvinist, assholes. Those individuals who can't even be bothered to endure the torment of a male teacher lest they be patronized or spoken to with a tone of condescension are probably not well balanced people.

From another perspective, would you think it reasonable for black men to avoid tech because of "a thousand previous encounters with [white]men who were abjectly unable to interact with [black individuals] in a way that left them feeling comfortable"?

Then he and you should take it up with the women who have had these negative experiences, whose prejudice you both are supposing, and not me. Do let me know how that goes.