The acting in the 'Telephone' video is really cringey in my opinion. To which, her stans always say "it's meant to be bad! The video is campy! It's not meant to be serious!" But it doesn't seem campy at all. She just looks and sounds so bored/flat, so I can see why she hates it, even though it's visually great. Her performance is just bad.
she's said that ages ago. she's really awkward when she talks about it. i think it's more so about the behind the scenes process rather than the song itself.
As for the video I think she said in the same interview that it was just way too many ideas at once. I like it for the campy/humor aspect but I kinda agree. I even think Alejandro works way better with a common theme/aesthetic throughout.