Affectations menu name

No, it should not : Assignment is a term used to define the link between resource and activity. Reosurce is assigned on activity for some work.
Affectation (even if not the best term) defines the link between Resource and Project. The resource is affected to the project (means the resource is part of the project team).
If you really want to change some terms, you may concider using the plug-in "personalized translations"