HaLeiVi, now you’re singing a different time, one I agree with you on. No one implied or suggested, that I know of, that anyone not hold the door open for everyone/anyone and, rather, let the door “slam shut” (as you described it) in the next person’s face. Of course hold the door for everyone. The issue only is when one makes gender-based distinctions on whether to hold the door or on which gender should hold it for the other.
We can be honest, the door holding discussions invariably revolve around the issue of gender. Whether it is being discussed in the context of shidduch dates or more generally. Rarely is it being discussed in the sense that everyone should be holding the door open for anyone in front or in back of them, regardless of their and the other party’s gender.
If you failed to see that fact then you’ve been running around with your eyes and ears closed.
Syag, why would you find an insertion of a Chazal into the conversation as “odd”?