As a society we acknowledge that sex crimes are worse compared to other crimes that are physically similar. "Rape is just assault" and "sexual assault is just assault" makes no sense even if it's technically true in some particular definitions you have, there is a reason we use a different word to describe crimes that include a sexual component, because we recognise sexual crimes as particularly heinous and degrading. Similarly, all labour is coerced but we recognise that coercing someone into filling out an Excel spreadsheet, while wrong, is not especially heinous in the way that coercing someone into sex is.
If snatch someone off the street, drag them into my condo, and force them to fix my toilet at gunpoint this is kidnapping and forced labor - something I'm going to guess has a much bigger penalty than breach of contract.
Rape is analogous to the latter, not the former.
https://www.ilo.org/global/topics/forced-labour/lang--en/ind...