And yes, the people against the Huntress costume are ignoring other costumes. The mere fact that there are worse costumes out there, but they choose to focus on this one in particular is ridiculous and that's why nobody outside their group takes them seriously.
There are a lot of costumes that show more skin than the Hush/Huntress. The issue with this costume is that it is impractical for the job. Huntress is not a meta. She is fighting criminals who use weapons. Her costume should be practical. It is not. It makes her stomach a target for bullets and arrows.
What's worse is that she had a somewhat practical costume (that "somewhat" being aware that there will probably ALWAYS be some fan service in female costumes in comics) and it was changed to the Hush one. And then it was changed back to a practical one and then it was changed again to this impractical one. And the excuse for the change has never been about its practicality but rather what the comic book creator, in this case Tony Daniel, liked. Specifically he said:
"Um let's see - the Huntress I went to Jim's design for 2 reasons, the first is I feel it is sexier and she pops more. The other costume is too much black, which is fine, but in the book there's so much black already. And I like showing some skin when I can"
I don't actually have a problem with Catwoman's various body exposing costumes. Catwoman is not a crime fighter. But when she has been a crime fighter, say, in her stint in the Outsiders or some of her activities during her later run, her costume was practical. It was one piece and fully covered her.
And if there is actually a group against the Hush costume I would assume it is the group known as "people with taste and good sense"