Good insight. Wanting to excel and wanting to win are two different things, or maybe one at different points on the same continuum. A matter of degree. Pressing yourself to excel is good I feel because you take pleasure at achieving something that took focused effort, whereas in winning some take pleasure from the fact that someone subdued/dominated another.
On a tangent, a thought I always have liked is in the Sun Tzu book, in which it is asked, "What is the object of war?" Someone answers, "Victory," and they are told that's not correct. Rather, it's "Peace." The knowledge behind the exchange is that "victory" is not lasting, and often prompts retaliation in a new try for "victory," in a cycle of violence. And that is where an excessive thirst for "winning" on the mat, can be dangerous, not fun, and distort the mood/culture of a school.