Someone with reasonable grounds to suspect they may be on this (i.e. "vaguely related to the publishing industry, currently or formally) PLEASE go ahead and make this all about data protection. If there is a list of people, there is also a lot of "personally identifiable information". And if you're organised enough to run a support group and call yourself such (and run a Twitter account in that name), it's also at least plausible that you're some sort of an "organisation".
Data subject access requests, followed by requests to rectify, followed by insisting on your "right to be forgotten" and for all records pertaining to you to be permanently deleted. Demands that the mere list entry doesn't include the source data, and unless they've made it up (in which case it's defamatory!), they must be in possession of that, too! You name it! Extra bonus points for "also, I'm an EU national, and as such am demanding this as per EU GDPR; no, that law doesn't care about Brexit, it doesn't even care if you're in the Maldives and were never in the EU to begin with!" And, in case of failure to react, reports to Twitter, ... andsoonandsoforth.
And, no, the idea is not even to take this to court (if you manage: good on you, but: chances are they're not even, technically, an actual organisation capable of responding. Also, I'm not a lawyer!). The idea is rather ... data protection compliance stuff is some of the most outrageously annoying stuff you'll ever have to deal with in your life. Even if you're completely right, it's still ridiculously cumbersome to gather the evidence of this, document, and demonstrate that you are. So, the idea is, basically: administrative overload! DDoS, except: not on machines but on organisational capacity.
I'd quite enjoy it - sadly, I haven't published anything at all ever since I got my letter to the editor printed in the local paper at around age 12.