There should be no retribution or guilt in unfollowing people, though perhaps if they are a close friend you should consider the message that sends (like it does in FB).
This is a blogging platform so you should use your friends lists solely to highlight content of interest to you.
The difference in Facebook is that you don't get an 'unfriend' message. You just notice over time. GinaBOT however tells you everything, so you see it right away.
In the case of Steemian Two I guess he uses it too as he was very quick on the trigger!
I would imagine most people aren't obsessed enough to be running GinaBot :)
Even if they are, if it isn't a friend you are not making a statement about why you unfollowed them. Their content just isn't of interest. I unfollowed somebody yesterday on Steemit.
GinaBOT is well used by many and by you I believe! I want my information on the go and its one of the best tools on offer.
There's a couple more I'm thinking of purging, no reason to keep them there if there's nothing of interest to view.