This is a useful term to describe a group of people, usually male, often young, and subject to some form of orderly discipline, such as marching or riding in formation. Boy Scout troops, and cavalry troops, are good examples of this usage.
Unfortunately, this sense has been blurred by the media, where the word is used to mean individual soldiers or perhaps marines. "Six troops killed in ambush" is a typical newspaper headline.
As is usually the case when a word is misused,one can't prevent this. The best I can do is to deplore it.