I tend to agree that many interpret something with a generally positive aspect to it to be campy. If they really need a dismissive word then perhaps what they want is "corny" which means something much different than campy.
TOS could do all kinds of stories yet throughout it was generally positive and idealistic, things that are seen as "campy" today. And note that a lot of film and television SF tends to be edgier, somewhat darker and cautionary about the future.
was a lot like TOS in terms of its storytelling and by contemporary standards it, too, might be labeled as campy, but it (like TOS) was certainly nothing of the kind. Same with Babylon 5.