Actions can have unknown consequences. Having sex with a teacher and married woman is likely to have them, even if in this case the specific consequence is unexpected. It's a risky decision in general.I'm reasoning from the perspective of a player who bought the game in steam in 2030-2035 after it came out.
If you look at it that way, and not in the format of annual updates, when we have the opportunity to replay the game 10 times, the game does not withstand any criticism.
And that's not an answer to the claim. The player is not a prophet and he could not have known about Jade. It's his fault for not knowing.
If this was just a porn game that could be glossed over. But it was pretty clear to me from fairly early that DPC wants to tell an adult drama story. Since then I've approached every decision I've made from the perspective of "my main LI(s) might likely find out about this," at least on runs where I care about the main relationship.