But, I'd argue that things being viewable without being absurd wins out over "fashion in the future could be odd."
They're supposed to look ridiculous and absurd, especially from Katniss's point of view. The book takes it much further, with everyone having grotesque cosmetic surgeries, not just bizarre make-up, tattoos and wigs. If anything, the movie toned down the way the book presented the people in the capital.
When you're looking at characters and can't take them seriously while they wear ridiculous outfits, have devil beards and look like Lady Gaga rejects it's hard to fully take them "seriously" as credible villains/characters.
I'm not sure who you mean here. The general population of the capital aren't the villains...not directly. Katniss views them with disdain, disbelief, even amusement, but definitely not seriously. If you had the same reaction, then you're in Katniss's headspace, which is where the filmmakers want you.
The actual villains, Seneca and the President, are both very toned down. So is Cinna, who you're supposed to take seriously as Katniss's ally. The only character who looks like a capital freak is Effie, and like the others, you're not supposed to take her seriously at all.