The User Authority algorithm that @steem-ua uses effectively judges you at least a little bit based on the ratio of people who follow you to people you follow.
Following inactive accounts reduces the authority you can pass on to active accounts, who pass it back to you and on to other people in your network, as well as growing your network. So unless there's a significant reason to keep following an absent user, it makes sense to keep your follower count to people who are actually here, if you're participating in UA. If you aren't then it doesn't really matter.
How is this affected by inactive accounts that are following rather than followed?
There doesn't seem to be anyway to remove these.
I don't know the algorithm, but under the basics of UA as a concept having people following you shouldn't reduce your score no matter what. I have reason to suspect that may not be true here, but nothing I'd consider evidence, and the effect doesn't seem to be large.
In any case, as you point out, there's nothing you can do about your followers, so don't worry about it.
Interesting, thank you. I wasn't worried, only curious.
ok, that makes more sense, thank you, I keep a fairly short following list but if I have a problem with a UA score I could pare it down more. Thank you!