Consider yourself fortunate. I’ve been told on more than one occasion that my holding a door was denigrating to women.
Several years ago my morning radio partner (a female) told a story about seeing a bumper sticker on a woman's car that said, "Proud Feminist". My morning partner said, "Oh, she's a feminist? How cute!" I laughed so hard my belly hurt.
The proper response is, “I didn’t open the door for you because you’re a woman. I did it because I am a gentleman.”
I have often held a door open for another man, I wonder why they never complained.