One advantage of base camping is that you can spend the time to dig a deep hole.  I generally dig a hole at least a foot deep and a foot wide to use with a portable seat.  Digging the hole generally takes about a half hour.  But once it is set up it is comfortable and everything goes in the hole.  At the end of the week, it is buried a foot deep. Other than some dirt there is no sign that it was used.  The thought of carrying used TP to my campfire seems like a much worse idea.

Many years ago my wife and I went to the Dominican Republican to a nice resort.  Because the resort was having sewer problem, the resort wanted you to put the used tissue in a basket next to the stool.  I never did and judging by the tissue in the basket very few people did.

The real problem is, of course, people who do their business and make no effort to cover up when they are done.