Well get to work. Give some ideas. Instead of whining like a child at the grown ups who do.
The question was why. Now you have some insight why. Fix it.
I don't even think the "use maxima" was yours, and if you pay attention the argument is literally
"Make her a Eugenicist and a tyrant" a complete monster as I said l and even then... it will be EXTREMELY difficult for her to be taken seriously overall, because
her whoooolee shtick is still wrapped up in nookie/reproduction. Terrifying.
So unless she's a preying mantis you're still working in the confines of that same system.
Moving on.
Trying to look away from the actual reasons won't help. Ignoring things that might help doesn't either.
Primarily, look at the villains that do work
I mentioned Grendels Mother for a good reason, it was a villian that WAS taken seriously. The movie kind of lampshaded the whole thing.
I also mentioned the old crone for a good reason too because you know what villian could VERY MUCH be taken seriously?
Baba Yaga.
That's a female villain that is simultaneously "Unsympathetic", Dangerous, and Commanding".
Magic in DC is very powerful and she is 1. On earth and 2. A final boss type.
I recently came across her in SCP-form
http://www.scp-wiki.net/scp-352
So extrapolate her a bit for the DC universe. She's scary... superstrong, indestructible, and can become a world power, by essentially granting wishes or because people just freaking worship power.
To the Op: asking a question like "Why can't female villains be taken seriously" opens an important discourse.
Which does indeed touch on things like "What makes a compelling antagonist"
However, we shouldn't lampshade it at all if the conversation is to have merit. The true answer is "Sex" its hard to take a villian seriously if they have too much sex appeal, because there's too much concern
with jumping their bones than putting a hard stop to their evil. I shouldn't be that way, however, we should acknowledge that it is.
I mean... for years a Poison Ivy's whole thing was "Kissing" people. The Female Furies could work but Lasher is a a literal Dominatrix, and one of the other's is an angel faced rival cheerleader type.
Amanda Waller. Is a more terrifying for than Ivy, Harley, Maxima or the Furies, because her power, nor her appearance implies "sex". Further, when they made her a model in the new 52 it was outrageous.
So. yeah. Look to Amanda Waller, who is taken 100% seriously. If she was truly evil she'd be a danger to everybody.