There’s plenty of sexual assault examples in trek both men and women, this is not one of them. Riker was not forced into starfleet, was not forced to accept the mission. He is an undercover agent performing what constitutes as espionage for Star Trek TNG era, this is one possible outcome of accepting that assignment and it’s even implied he will need to perform something like this if things go wrong and he is told of all these outcomes way before this mission even happens. There is no difference to this than Bond hooking up with the BBEG’s side piece to gain information or access. The reason Riker looks disgusted with the situation is because Frakes is giving that character morality and is emotes in such a way the audience understands that “Riker doesn’t want to do this because it’s beneath him as an enlightened Star fleet officer”. It’s not rape or assault, and saying it is demeans actual sexual violence.

Data being abducted by the collector is a much better allegory for rape and human trafficking than this scene, there is zero consent to that situation.