He and Perikatan Nasional need the attention. Going against the royalty while claiming to defend Malay rights is exactly the strategy that a theocratic state engages in to attain hegemonic control.
The spectacle of Mahathir defending his speech would galvanise not only his political fortunes but would serve the agenda of the theocrats-in-waiting.
People who vote for this religious extremist organisation who for years were taught to obey and respect the feudal culture would turn themselves over to another kind of theocratic feudal system.
Now rational people can have their views on the royal institution in this country and those views may very well get them in trouble with the law...