An old man can truly appreciate beautiful young girls, unlike ungrateful young punks who are just horny. They are inexperienced and don't know how to truly savor a girls beauty and spirit.
If I had to pick between being a young generic h-doujin MC (probably named Yu-kun or something) having vanilla sex with a girl and being a gross old man with week-old smegma dick forcefully fucking a girl into oblivion, I'd pick the second option for sure.
They just seem to have much more fun. Also, all old perverted men are automatically incredible sex gods according to hentai logic. Since being a perv means you're super well versed with sex acts under any circumstances, and being a 50+ year-old perv means you unlock a perk that lets you pull out mind-breaking, irresistible aphrodisiacs out of thin air.
Welcome to the Boomer's world. They spent their youth dancing in the mud, taking drugs and having sex, spent their middle-age in yuppie culture, building fortunes for themselves off the backs of their parents, and now they're hogging all the high-paying and middle-management positions whilst the government pools taxpayer money into luxurious boomer pension pots. They're the generation that took the post-WW2 world of white colonial power, rode off the hard work of their parents, ruined the environment, destroyed the nuclear family, had it easy their working lives, and now aim to destroy any chance of the next generations having it as good.
If you're a young pretty anime boy in an h-doujin then here are the options laid out for you:
>You fuck the girl
>You get fucked
>You get blueballed forever because that's a fetish
>You get NTRed for a fat old man
If you're a fat old man in an h-doujin here are your options:
>You fuck the girl
>You fuck the girl so hard she ditches her pretty anime boyfriend for your superior dick
>You fuck the girl so hard she becomes a mindbroken slave to any of your sexual whims, without question
>Protip: the last two aren't mutually exclusive
Who the fuck do you think I want to be?
But if you take the old man alternative you could have schoolgirl twins competing to suck your dick while their mother is rimming your ass, how is that going to ruin your day?