I'm going to wash my gf's kitchen towels with her bathtowels
Does she want you to wash those towels together?
No, she said she doesn't like the kitchen towels in with the towels she uses to dry her feet.
If your girlfriend doesn't want you to wash the kitchen and bath towels together, then you shouldn't. You should respect your girlfriend's wishes and wash them separately, because actively doing something that your partner requested you not do is really inconsiderate.
I'm the man and I do what I want.
That's not a great attitude to have. You shouldn't just ignore the requests of your partner. You should just wash them both separately.