I don't know JP's motivation as I only ever knew him in passing, but Sammy was running the studio and there is a niche/fetish market for older/younger content. You make videos to sell videos, so if there's something that will get sales and you are okay with performing in that area, you do it.
You basically have 4 types of content if you are in the industry. There's stuff that's a personal turn-on, stuff that doesn't turn you on but you are comfortable doing, stuff that turns you on watching but would never do yourself, and stuff that is neither a turn-on nor something you are comfortable with. If a scene is either of the first two types and would sell, you film it.
I do know in Sammy's case that over his years in the industry, he had numerous custom video requests he wasn't comfortable doing. In each case, he turned down the request regardless of what the monetary offer may have been. Physically being turned on in every scene he filmed was negotiable, comfort with an act in a scene wasn't.