Most Masto/Pleroma instances are too small to be worth the trouble. I get about 1-2 spam bots signing up per week, usually deleted automatically or within 1 hou

Most Masto/Pleroma instances are too small to be worth the trouble. I get about 1-2 spam bots signing up per week, usually deleted automatically or within 1 hour of signing up (longer if all the admins are sleeping). Small instances that don't do anything about spam usually get defederated fairly quickly. With the way federation works, your reach is very unpredictable and you need to attach to very large instances if you want to have any effect. And large instances have more moderators to more quickly handle them. Per-user mastodon probably has more moderators/administrators than comparable services (twitter), so it's a bit more clean.