In the 70's and 80's my daughters wore culottes. I was able to buy them but I did have a pattern to sew them also.
Approx 1980, an untracon church did allow them, but the pastor's wife had to see the pattern and approve before you could sew it up.
Many of the culottes in the 60's looked like a skirt. Unless you took huge steps it hung like a skirt, had fullness of a skirt and was no doubt classified as a skirt in stores. In fact it went by the name "split skirt" not culotte....