I am an exempt non-managerial employee. Although it is not my job title, I would say I fall closest to the outside sales exemption for Ohio.

I received a memorandum from my boss stating that I was "required" to work 50 hours per week or it would "result in action up to and including termination". I know I cannot be docked pay for what the company views as partial day absences - meaning I'm not working 10 hours a day, but can they terminate me for it? How is this not treating me like an hourly employee? My primary job duties have been fulfilled for almost 6 weeks, and I'm still putting in about 45 hours a week.

Contrary to popular belief, being an exempt employee does not mean that they cannot be held to a specific schedule. The employer can require that you be there for specific hours during the work day, and if that adds up to 50 hours per week, well, many, many exempt employees work that many hours, or more.