I think those examples still fit what I was saying, and maybe I was explaining it poorly (and it annoys me that second site is inconsistent with the usage).
I see pant as a cataloging word, so I read "This is a relaxed fit ladies pant, with a straight leg" pant as describing the category of garment. It would still be appropriate to use it that way when listing an item online, because that is not a listing for a single pair of pants. There are dozens, hundreds or even thousands of items available under that one listing, and so the description is general.
If I were working in a store I might hold up an individual pair and say, "This pant would look nice with that top." but I would be referring not to that particular pair of pants, but to the whole rack of them... all the the pants with that item number as it were. "This style would look good" or "this product" not "this item"
If I you tried a pair of the pants I might ask "how did that pant look?" again, not referring to that particular pair, but that style, that item. How did those pants fit, that particular pair. When I ring you up, I would say, here are your pants, because now they are a particular item, you have bought a pair of pants which are a relaxed fit, ladies pant."
Maybe others don't hear this distinction, or use the word to make it, but I always do.