I don't understand how that is stupid
I explained about Jill's Character long ago in this
Post that It's because of her family's expectations and restrictions that she is like this. The more appropriate term for Jill in that Ep7 scene should be that she is shy and inexperienced in talking/asking things like this.
For comparison, Jill is more of a romantic character whereas Sage is more of a sex-loving character, which she is. There are very less romantic moments with Sage and more of sexual moments/talk.
DPC already did a great job by giving each girl a different personality. One can choose Quinn, One can choose Josy, One can choose Bella. You can't blame DPC for adding no lewd scene for Jill, she is not like other girls, if you are that thirsty for sex scenes, there are other girls, go for them.
Jill is loved by those who prefer romance more than anything else IMO. There is a positive sexual tension between Jill and MC which I love and maybe some others too.