it seems to me you are twisting concepts to fit into your particular political viewpoint rather than objective fact.

Words have meanings.  "Madman" has a meaning, and saying that anyone who commits a mass murder is a "madman" is just a distortion of the meaning of the word. No, people can come to the decision to commit crimes based on their understanding of the world and not be "mad".

Saying "there is no  reason to hate Muslims or any identifiable group since they are composed of individuals", etc. is actually saying "there SHOULD BE no reason", etc., but that is obviously not how many see it, and the same can be said of hating "conservatives", but plenty do too. That does not mean anyone chooses those groups "arbitrarily", that word has a meaning, too.

The target reflects social conflicts in a society. In ours, currently, social conflict is between identity groups, involves religions, and political and social policies regarding them, that is what this crime reflects.