I have a few ideas of what this person in Houston could be using them for. For starters, wet diapers make
outstanding fertilizer, especially for stubborn soil. (Dirty ones aren't really useful for this purpose, but if the term is being used to refer to any that are just used, it could be for this purpose.) Turning wet diapers into compost is very easy if you know how to do it.
Also the other unregistered user mentioned, (it wasn't me,) there are some people who enjoy smelling dirty/wet diapers. They're completely harmless (at least as harmless as any other group of people,) and just have a peculiar interest. To put it bluntly, they're interested in your garbage, not in your kids. (If anything, they're more likely to spot and report actual nefarious behavior as they don't want people conflating what they're interested in with something that's truly nefarious.) I'm also aware of people who use dirty (usually only wet, but sometimes ones with poop too,) diapers inside of a plastic bag to massage their feet with, and even some who just enjoy photographing them. (I'm not making that up, there are people who just enjoy photographing wet diapers.)
Additionally, it's worth pointing out that small-scale diaper recycling for wet diapers isn't that much more difficult than creating compost from wet diapers if you have the space and capabilities to do it. The biggest obstacle to such an initiative is usually having diapers to work with. Again, this doesn't explain why someone would want "dirty" (poop) diapers, but "dirty" could be used to describe any used diaper, and larger diaper recycling facilities can accommodate fecal material.
While I'm nowhere near Houston or Texas at all for that matter, I could definitely put a bag of wet diapers to good use. Maybe I should see if someone in the middle of NJ is willing to let me have some.
