Why do civilian employers hire vets for managers or sales?

There are several reasons: Vets have less inhibitions when speaking with strangers. Most sales need a dominant personality (Vets are usually alpha-types). Professionalism. Time management skills. Understanding of rules, regulations, and such. Multi-taskers. Loyal. these are just off the top of my head... I am sure there are about 10000 more!

Well regarding sales positions, that is one of the functions of any military recruiter. Selling a contract to some kid who has no idea what he wants to do with his life. So frankly, I'd think military would do well in sales departments because we have to sell ideas to higher ups and the junior troops and convince them why it's a good idea.
Regarding managers, I would say because most of us have been in some form of a leadership role managing teams of troops. Experience is a valuable commodity that typically can't be attained in school. Sure you can get experience in the job market, but can an employer really verify if you are a good team player or leader. Military members on the other hand, it's practically in the job description.