IIRC the only scenes where condoms are mentioned are a scene with Jamie and Shauna (and as you said, you don't have a problem with Jamie's reasoning) and a choice with Tia, which is, well... a choice.
Rachel's clients obviously want to get pregnant, but so far we don't have confirmation that it happened given that in-game it's only been 9 days.
And unless stated otherwise, I would assume the rest of the girls are on birth control, or don't have an issue with getting pregnant.
I get it, to you that last part needs more justification, so as I said, this VN might not be for you, and if you stick with it you'll probably find more things you don't like.
Or you can accept it and keep playing for the wholesomeness