I enjoyed your analysis. I think Akio's interactions with Utena in the Black Rose saga are interesting for the reasons you outlined, nothing actually romantic or sexual goes on between them, but there's definitely grooming going on. He's presenting himself as the dependable, wise older man she can confide in.

One thing I wanted to mention while we're on the subject is how in so much of the Utena fandom, I see people blame Utena for her encounter(s) and relationship with Akio, calling her a slut and whatnot. I really don't understand this perception because to me, that's basically blaming a child (Utena) for not having better judgment. It's always been apparent to me that the Utena/Akio relationship is not entirely consensual -- true, it's not rape in the sense that he's holding her down and she's screaming -- but it's definitely statutory rape and what I like to term "dubious consent." In spite of the fact that it's fictional, the Utena/Akio relationship is, to me, is a perfect example of why we have statutory rape laws in place. Not because of an 18 year old having sex with his 17 year old girlfriend, mind you, but because of adults in position of power who take advantage of someone who's underage and obviously too naive and trusting to properly consent.

I really don't blame Utena for anything that went on during her dalliance with Akio, because to me she's a naive, trusting child being taking advantage of and used by an experienced, manipulative adult. That's why I feel like Akio trying to shift blame in episode 38 is so wrong, and why Utena was so on the mark to say "That's different!" Akio was an adult who knew full well what he was doing, and Utena was a naive, gullible child with poor judgment. BIG difference there.

Also...

Anthy is a fucking terrible person, people. She's not as bad as Akio but that's a bar so low it's actually molten lava.

I don't disagree that Anthy definitely does some reprehensible things throughout the series, but for myriad reasons, I have trouble viewing her on the same level as Akio. I love to hate Akio, whereas Anthy, I wind up feeling empathy and compassion for more than anything else. Among other things, there's the fact that it's hard to tell how much of Anthy's wrongdoing is of her own will, and how much is her being basically coerced by Akio. I think some things (such as her tormenting Nanami) are of her own will, but that others, such as the aforementioned bringing Utena to Akio, are definitely her doing Akio's bidding. Also, the fact that I believe Anthy is pretty miserable doing what she's doing, whereas I think Akio enjoys every second of it. Add to the situation Anthy's perpetual torment + abuse by everyone around her, and I feel it's pretty easy to see Anthy as a sympathetic character compared to Akio.