You seem really unsure of your cats needs sometimes. She probably feels the need to educate you or that you don’t know how to care for a cat. I’m not trying to insult you just maybe she senses your unsurety sometimes. Try to be assertive and confident, then people don’t make silly assumptions.
Hard to say with confidence but its possible your vet is trying to take your MH into consideration and trying to be kind and extra nice to you but it comes across as condescending.
My dentist was like that at first. One time he even said “good boy” to me once (I was 29 years old). I think just try and ignore it and act like an adult and hopefully they tone it down as they get used to you. Its what happened with my dentist.