[wjnc]

Would you mind explaining how "step it up", which I read as "stepping up the dress code" is low-class? For me there is a natural progression from sports wear, to casual, to business casual, to business, to cocktail casual, to cocktail, to black / white tie.

And since we all have that one friend or colleague that's always two levels below the stipulated dress code, I also understand the urge to explain it in male / female terms. It's just more specific. If I extend my sympathy to the non-binaries, I could understand that the dividors "Men:" and "Women:" could have been dropped in the explanation. But why is that such a big thing?

[nabnob]

Because the dress code for women is more sexualized than the dress code for men, and also expects women to wear heels, something that's not healthy and bad for your joints.

[belorn]

A common reason for the anti-necktie sentiment among workers is that the tie represent a symbol of submission and slavery (i.e., having a symbolic chain around one's neck), marking which males are lower on the social ladder and thus unsuitable mates.

[happytoexplain]

The disrespect of "step it up" is derived directly from what people are being asked to step up to. The phrase by itself has no context.

I'm not following your second paragraph - it sounds like you're simply saying that the female and male version of the dress code in question have no differences in terms of respect and reasonableness in-context, but surely that's the crux of the disagreement? The point is that I find "wear a short dress and heels" to be more disrespectful than "wear a blazer/slacks/suit". I am making no comment on how those two things are comparable in other contexts, e.g. whether or not they are members of the same dress code by definition. I can't follow how that relates to respect.