Do you have any idea why some people’s Twitter follower count either stays the same or slowly drops? Mine used to climb pretty steadily, but lately I’m losing followers even though I’m not doing anything different.
Most internet companies are more subtle than censorship-happy Facebook, which openly and proudly censors posts and bans users using a set of “community standards” so bluenosed they’d make a Puritan swoon. Google is only slightly less censorious, using secret algorithms to monkey with search results in order to boost its advertisers and “de-weight” any site containing “adult content” (which is why my traffic to this blog from Google is only about 1/6 what it was seven years ago); it also “demonetizes” videos on YouTube (ie, makes them ineligible for moneymaking ads) using similar esoteric criteria. Twitter, by contrast, likes to represent itself as the most free-speech-friendly of the social media sites, and to a degree that’s no empty pose; it’s the only one left which still allows (some) nudity, frank sexual discussion, and the open presence of sex workers. But behind the scenes it still has a number of secret mechanisms, most of which it denies the existence of, that are intended to push nasty, dirty, sex into the shadows to make room for nice, fully-clothed bigots. One of those is the shadowban, a blanket term for a number of occlusions which can be secretly installed by the corporation on the accounts of (mostly but not only) sex workers so as to make their accounts much harder for new readers to find while allowing them to appear normally to those who already follow them: 
Twitter used to deny that there was such a thing as a shadowban, but as of January 1st its TOS states that it “reserves the right to limit distribution or visibility of content”, IOW to shadowban users. But what you’re describing is different. According to the shadowban checker I linked above, I’m not shadowbanned; yet my follower count, which used to increase by hundreds every month, has now been static for over two years. I get at least 10-20 new followers every day, yet my count just bobs gently back and forth like a buoy on a calm sea, as though something were draining away followers at the same rate I gained them. Then since about April, I’ve been slowly losing followers; it’s very gradual, about 220 followers so far, yet I’m still gaining a dozen to a score new followers evey day. The only thing I can figure is that this is part of their anti-bot campaign; apparently, the site is methodically checking every account over time, and when an account trips some condition that Twitter has decided makes it “suspicious”, that account is either closed entirely or at least “disqualified” as a follower. I know I’ve had a number of people tell me that Twitter has “unfollowed” me for them without their permission, such that they wondered if I had left the site until they saw someone else retweet me; I suspect a lot of the lost followers are due to a similar process. But riddle me this: if it’s an innocent by-product of that kind of routine site cleaning, why are all the people who have noticed it either “adult” or otherwise “controversial”?
(Have a question of your own? Please consult this page to see if I’ve answered it in a previous column, and if not just click here to ask me via email.)
I recommend reclaimthenet.org as a source for both technical and political fixes for big-tech censorship. And gab.com, a twitter-like app that doesn’t ban anybody (though they may tell on you if they see illegal activity).
And especially protonmail.com, an encrypted e-mail service in Switzerland. A basic account is free.
There’s also http://gnu.io and http://switter.at.
The problem is that automatic bot-detection is actually very hard to do. Sure, somewhat smart humans can usually spot them immediately, but machines cannot. There is a somewhat similar problem that is unsolved and usually devolves in some kind of arms-race: Detecting cheaters in multiplayer online games. Again, easy for somewhat competent humans, very hard for machines and the algorithms used are easy to circumvent, do they require re-adjustment all the time.
Hence I expect what you are seeing is some kind of side-effect of that arms-race. I do not think that “adult” or “controversial” users are targeted intentionally by Twitter. One possibility is that people are complaining less when they get “unfollowed” to such a user and feel sort of watched and do less often re-follow. That may also lead to a worse calibration of the bot-detectors for this case.
Just remember that computers are complete morons with no understanding at all. And here they are tasked with making decisions that require some level of sophistication. Of course that does not work well. At the same time, it is all about money for most/all social networks, so they will use humans to look at things only when they really cannot avoid it.
My recommendation would be to occasionally tell your followers about this forced “unfollowing” and ask them to just re-follow. If that reverses the effect, you have both identified the cause and fixed the problem.