YouTube seems to use a fairly unsophisticated system to link "related" videos, presumably based on the tags and descriptions which the posters themselves supply. Some of the videos an item links to are useful, some are only vaguely connected, while some turn out to be serendipitously interesting.

If you think of all these simply as examples of military music it is hardly surprising that they are linked together. It is only the surrounding connotations which makes it seem strange, but that is probably too complex an idea for YouTube's computers to deal with. Neither, perhaps, should they - after all, if you are interested in examples of military music then you would be interested in these links. I think most people are capable of making their own decisions over which suggested links they wish to follow.