Most exhaust vents are hard wired, not plugged in to an outlet for the reasons you cite. (I've never seen one that used a plug). Choose a different vent if the one you're looking at specifies a plug connection, or check with the manufacturer whether it's ok so substitute hard wiring for a plug set.

You will have an electrician install a "whip," which is a cable hanging out of the wall in the vicinity of where the hood's integral junction box within it's own housing is located. If it's an insert style hood, you will mount the cabinet/enclosure of your liking. Then you will connect the whip to the hood insert, install the hood insert into the cabinet/enclosure. and if ever needed to access the wiring, reverse the process.

They can always install an outlet up there like they do with wall-mounted TV sets.