Honestly, it depends entirely on the bird.
When I first got into bird keeping (about 13 years ago), many owners were afraid to groom their own birds and left that to groomers and vets who would do it for them. Too many were afraid that if they were the "bad guy" that it would break the bond that they have with their bird.
Now-a-days, it's quite the opposite... owners are more confident in themselves, some are teaching their parrots certain behaviors to assist in being able to groom them (i.e. spread wings so owner can trim the flights, or lift foot so owner can trim nails) rather than having someone else do it.
If it was true that a parrot should hate their owners if their owners groomed them, then by all rights, Charlie, my mitred conure, should hate the living daylights out of me! I've had him for nearly 7 years now. Shortly before I adopted him, he had tried to bully a blind ruby macaw and got the short end of the stick... two surgeries later and he's missing half of his lower beak. He can eat and drink just fine, but since his beak no longer aligns properly, it 'scissor beaks' and he has to have it trimmed for the rest of his life. That could be another 6 to 10 years (going off of the average expected lifespan of conures) or it could be for another 20 plus years!
Charlie's foster mum showed me how to trim Charlie's beak and we did it together. Since then, I've been doing it on my own for almost 7 years now. There was one time that I thought I could pawn the job off on my a-vet (after all, it's a two person job I'm doing alone!), but that turned out worse than I expected, and I still had to finish off what she didn't do...
And through all of this, Charlie remains "my-turd"! He's bonded to me the most out of anyone in my family! Sometimes he allows my sister to interact with him, but she has to do so silently, otherwise he'll attack her! (my sister and I, being near 3 years apart, still look pretty similar!) He has very limited interest in interacting with anyone else who's not me and does not take the time to earn his trust.