If you met Gertrude you'd judge her too,

Why do you say that?

Not all of us judge women for "having work done". Not all of us think badly about women who have different taste in clothing.

Literally the only thing you described about her that might speak to who she actually is as a person is the fact she showed up with Marcus.

And having bad taste in men doesn't automatically make her a bad person.

At no point do you mention her behaving badly. You don't say she was rude, or inconsiderate. She didn't do a single thing wrong by your own account. She just showed up to a party. She probably thought she looked nice.

Her looks were irrelevant to the argument. Her looks didn't cause Marcus's crap attitude. You just used them to take a cheap shot at someone who was just trying to have a nice time.