I always roll my eyes a bit when porn games do the whole "oh how could you possibly find me attractive? My boobs are just too big!" trope.
I know you will find this shocking, but the average cup size is between B and C. Women tend to think average is perfect size ... Anything less or more is not attractive. Men tend to lean a little larger on preference ... But few like HUGE breasts, relatively speaking.
Most of the women in this game would fall outside the majority of men's and women's ideal breast size.
Now, if someone is a fan of this game, they are likely members of the minority group that like 'em bigger than their head. But the trope has truth in it.
Also, someone with a low self image will find everything they can to validate their view of their low worthiness.