I am not sure you should be posting this on KYM, man… You just posted an image of a kid sucking dick.

In mythology, Roland went into an insane rage at some point, with the only thing that ended up calming him down being Astolfo dressing up like a girl and coming onto him. Also apparently Astolfo was a majorly effeminate pretty-boy in mythology, but in the normal sense, not the "is pretty much a girl with a penis" sense.
Nasu and Co. just took those facts and exaggerated them into having him be a habitual crossdresser that looks almost completely like a girl.
It still is indeed blatant fap-bait, it just has precedence for its existence.