Bless Your Hearts....
The reason a person might find household appliances as holiday gifts insulting is because it says, "This is your job, not mine.".
We've moved beyond the 50's. Everybody pitches in now. Wives have jobs and husbands vacuum and wash dishes.
Imagine a married lesbian couple on Xmas day.
One woman gives her wife a dishwasher.
Why?
A dishwasher is a household necessity, as is a vacuum or any other appliance.
Might as well buy her a snow shovel.
She's a partner, not a maid.
Get her a bathrobe or a kegerator, I don't know, anything but cleaning tools.
Of course, if a couple has a pre-agreed arrangement, such as, you keep the windows clean, I'll keep the floors clean, or something like that, it would be a little different.
Still, not the best choice.