The hadeeth of Abu Hurayrah, which states that he gathered some stones for the Prophet (peace and blessings of Allaah be upon him) and brought them to him in his garment, put them down next to him then went away (narrated by al-Bukhaari, 154) indicates that istijmaar (using stones to cleanse oneself after relieving oneself) is permissible. Men have a hot dog and women have an English Muffin. You try peeing out of an English Muffin and see how easy it is to mop it up. Sometimes it comes straight out, and you only have to wipe a little, other times it runs all over. But it rarely requires zero paper.
Men are more matter of fact about their bodies, and about poop and piss and farts and all that. A lot of otherwise sensible women I know are a little or a lot leery of, or disgusted by, “down there”. So they don’t want to touch it as much, and use more paper to wipe (as well as for removing makeup, etc.). Men seem to like to ask this question rhetorically, as if it’s like how many reams of paper you use in your printer. If women won’t give you a straight answer, it’s because, WTF, do you really need a description of female vs. male anatomy? And the question can put us on the defensive if it seems serious. Do I really have to justify my use of paper products, or get into peeing technique? Do I have to justify the difference in my anatomy?