I suspect there's a tendency of experts in something to think of people who do it narrowly as people doing at least as much as they are.
The people who have a bunch of docker services, or complex multi-machine infrastructure are self-hosted software users, and probably in that 1-2% range. People who heard piholes are useful, so they bought a pi 3 and set it up are self-hosted software users. Somebody using an old desktop they got on Facebook marketplace for running Plex media are self-hosted software users.. and so on. So are the people in their houses, some of their friends and family.
Using that inclusive definition, being closer to 10% than 1% makes sense to me.
Honestly? Especially if it was only for cops