I think it's on-topic.
For the purposes of asking a question, the asker should be able to define terms. This is part of allowing people of all knowledge and skill levels to participate; you cannot expect novices to use the same language as experts. Nowhere are you obligated to continue using the asker's definition, although it might be helpful to answer their question.
The question is basically about finding a quality, very aggressive martial art that may or may not be Krav Maga. I think this falls under our recommendation question type. Although it can produce a list of answers, this question has very definite criteria about how to restrict that list and prioritize one answer (style) over another.
In general, I think there is a problem on this site with people thinking only in the context of the martial art they train. If someone wants to ask questions about martial arts for soldiers, there should not inherently be a problem with this.