Honestly, I think people might be missing the point with Red Path Io and Green Path Io.
This brings up something on my mind about Io’s red path: the current positivity there in red path is
so much that I really cannot neglect it and directly claim that “green is still the path to eventual happiness for Io”. When people were praising green path Sensei for rejecting Io’s handjob, I kept thinking that 1) this merely means the merging of the two paths that subsequently reduces the impact of the Stomachache choice on their relationship, and 2) like you mentioned, hasn’t this difficult decision already been achieved by red path Sensei in a much larger scale a lot earlier??? This only proves that there is still hope for green path Sensei; this doesn’t automatically mean red path Sensei did anything wrong.
Granted, the mutual understanding and consensus made between Io and Sensei in these two paths are indeed significantly different; green path seems to offer higher chances of future consenting Io sex while red path
kinda just embraces Io’s displayed asexuality. But that’s it. The potential lack of future consenting sex (which may not be true by the way) by itself in the red path is by no means something damning. What might be damning instead is in fact: 1) current Sensei will not be able to handle an asexual relationship, and 2) Selly might “punish” red path players with possibly blackout sex or other horrible things.
To me, reason1 is thinking way too far ahead while ignoring the remaining Sensei x Io journey that has yet to unveil, and reason2 is literally something we imagine to convince ourselves and scare everyone else who didn’t make the same choice as us (seriously, have we ever become good at predicting Sensei’s blackout sexual assault even?). Since there really isn’t any in-game indicator that implies the possibility of any planned misfortune for red path Io (an example of this would be “Pareidolia murmuring about punishing akira for disobeying the
destroy her command”), I will continue to remain brazen until the day something does happen
all because Sensei didn’t Stomachache Io or when Selly does dish out punishment; only then will I shit my pants and change my mind.
I said all that but I’m actually on green path

But not because I think green would be better (in all definitions) for Sensei x Io in a long run, but because I simply fucking refuse to miss content.