1. That's not how trust ratings are used. At least I haven't seen anywhere where someone who has committed plagiarism has been tagged by DT members. Plagiarism is a job for moderators to do. I believe you know how to use the report to moderator button
Right, this isn't (or shouldn't be) a call for DT members to act. If Ratimov plagiarized something, it's the job of mods to ban him for that--and I don't read Russian, so it's hard for me to judge Ratimov as far as citing sources in that language.Take a closer look at the list of sources from Ratimov. The link to the source that you are quoting is in the list of sources from Ratimov 
So here we have the Russian moderator essentially vouching for Ratimov, saying he did in fact cite his sources--or at least that's what it looks like to me. I'd be interested to hear from others on this. I don't know if it's a witch hunt or not.