He does ask rather courteously and you can accept or decline, so Tav's consent is still there (Though in regards to Gale's consent, I find the entire writing very disturbing as it basically makes a joke out of someone's boundaries and inhibitions to sex, which is in really poor taste in my opinion. But Halsin is only a part of the problem here as it is Tav that coerces and pushes Gale into accepting it in the first place.).
The disapproval if you decline is something which a lot of people have strong opinions about and I understand and respect how people may feel that it is rubbing it in your face. I don't pay it that much attention as there are a lot of places in the game where the disapproval or approval can feel out of place depending on your headcanon and where the game coding can't read the intentions or tone you had in mind when making the decision. There are a lot of ways to interpret the dynamics of what is going on there, and depending on your interpretation, the disapproval can feel warranted or out of place.
