Is karate a sport, martial (military), or what?

Check the letter of Sokon Matsumura. It answers your question.

Strait and simple: just as Matsumara, Itsu, Gichin Funakoshi all stated, KARATE IS BUDO (THE ART OF KILLING).

On Funakoshi's death bead he wanted the art to NOT become too much of a sport. By then it was too late. Play fighting, as animals do at a young age) became the sport element of karate-do. Japanese karate-do is the most destructive form of personal combat the world has ever known. look up Shotokan karate + full contact and most is too brutal to sow.

If one finds true karate-do not effective in any way, they must look to a different sensei or remain on the outside forever. - Gould

That depends on what you train and what you are being taught. Most martial art today is taught for sport, unfortunately. It is much easier to teach it for a sport and fun than it is for self defense. People like to be entertained. You yield quicker results if you train it for sport. People like quick results too.

Some martial art is trained for display too such as modern wushu. Some is just for exercise to stay fit. Some is just for personal development and self awareness. There are many reasons for training in a martial art and not all are for fighting.

Sport. In my experience, I have found karate of any kind to be of little benefit in any fight.

It is a sport.

A martial art can count as a sport if it has a compettive aspect, such as taekwondo, karate, and judo. However, martial arts that do not have competitive aspects such as krav maga, do not count as sports. Since karate is competitive, it is a sport.

That really depends on the person rather than the art I think. The art can be all of the above, and the mindset of the person and how they train is what's going to make the difference.

Karate is many things. Something to be respected. Try not to put something in a box to define it. It is a very old art, that is still very much in existence.