"unhelpfully" was deliberately chosen, to indicate that signalling disdain isn't helpful to the goal of teaching OP how to help their team. One could argue that it's redundant ("Focus on X, rather than Y" does imply that Y is unhelpful), but even so; reiteration for emphasis is a perfectly cromulent stylistic choice.

Surely if the OP is trying to help their team to communicate in a corporate environment, then teaching them the shibboleths like "upskill" will be helpful to (as you rightly suggest) meet the readers where they are? The team will be free to use them or not, as they choose. Whereas "banning" those words can only handicap their ability to corporate-cosplay, if that's something they want to do.