Most of those mons aren't even that bad. It's really not worth bitching about any of those UU mons because none of them are anywhere near as bad as Scrafty or Trevenant when they were in UU, and all of those mons you listed are actually usable and perfectly viable Pokemon in UU. Sure they aren't that great nor are they really staples of UU, and they are by no means some amazing Pokemon, but they're not gutter trash like Ambipom in RU. The only one that is questionable is Milotic, since it is overshadowed by most bulky waters, but it is an objectively decent Pokemon and can work if you want it to. Sure, they aren't as viable as a lot of the other UU mons, but they're not useless at all and have their niches that some teams may want.
Honestly outside of maybe Milotic, UU's tier list is pretty fine right now. UU does have some mons that are, well, less viable than the other mons in the tier, yes, but nothing currently UU is utter garbage like Ambipom in RU.