Dear Mr Kingscrusher,
although I perfectly understand that you don't want your internet chess (which is your free time enjoyment) spoiled by constantly losing to engine cheaters. And altough I agree that there are a lot of those out there and that it is quite a serious problem on the chess servers, I think that you are really overdoing it with your accusations. I am 100% sure that Dr-Zaitzev is not an engine cheater for the following reasons:
1. I know his real name and that he has a FIDE rating which is close to 2300.
2. I have talked with him while playing him (he appeared as a Skype guest on my challenge). Although his English is not the best (naturally, he's from Spain after all) which makes it sometimes hard to understand what he actually means (sorry, Zaitzev :D ), he said some sensible things that make me think, he really understands some things about chess.
3. His style is indeed quite irregular. He mostly plays "crap openings" in order to avoid theory but I have even had some theory battles with him (e.g. Ruy Lopez Schliemann) from which I can tell that he can play normally and knows theory if it's demanded.
4. In the middlegame I find that he often has really creative tactical ideas, which just makes me think that he's very resourceful. Of course that doesn't make him more suspicipous as, like everybody else, also he commits serious tactical mistakes from time to time.
I think that's enough reasons to be completely sure that Dr-Zaitzev is really not cheating.
On a different note I would like to say some words about your role in this controversy.
Although being able to report people for engine abuse is a necessary right in today's internet chess, you have appeared extraordinily often in such discussions. In the past I found cheating suspicions to be "your thing", e.g. you went a bit paranoid after the first marathon (where the obvious cheaters were detected), saying that everybody in the top 10 should identify themselves to lichess. I think that is a bit over the top, after all we do this all for fun and there were no serious reasons to have suspicions on any of the remaining players.
Also those suspicions / accusations can hurt people's feelings. I think that that kind of shitstorming during your stream and now in this forum is not a very gentlemanly way to go about your problem which in my opinion is the following: You can't seem to stand that there are people who are better at chess than you although they don't play according to the principles you think are "correct". Just accept it, Dr-Zaitzev is just a way more ressourceful and better chessplayer than you are.
Finally I want to tell everybody who took part in this discussion that we shouldn't forget that this is our free time, we want to have fun here and we should be a community that is friendly and respectful to each other. I am already quite tired of those endless discussions, let's just play chess and be happy that we can do this in such a paradisic environment as
lichess.org.
Cheers
Kabeljau