Opening doors, pulling out chairs, or otherwise "treating a woman like a lady" is rooted in the idea that men should treat women like porcelain dolls or delicate flowers. A man doing these things might not mean anything negative by it, but it carries a negative connotation.
That's not to say that no man should ever treat a woman like a lady, or act in an old fashioned gentlemanly manner. There are no shortage of women who want to be treated that way. But there are also no shortage of women who don't want to be treated that way.
Pulling out a chair for a woman who enjoys that treatment is polite. Insisting on treating all women a certain way because you think that's how one treats women is chauvinistic.
I once received flak for something as simple as holding the door open. This was a few years ago, but I got barked at "I don't need you hold the door open for me!"
It was a bit of a surprise and wholly uncalled for, as I do this for both women AND men. If I'm at the door, and it's not automatic, and there's someone coming up behind me, I hold the door for them.
I've always thought it of it as a point of etiquette, or respect.
It think it's important to distinguish between a school of people who were raised into believing in inherent superiority, and people who were just taught "this is polite behavior"