Please read the many write-ups by developers of well regarded privacy and security ROMs, such as grapheneOS and divestOS.
Who detail in great length why root access is a bad idea, and why many apps that require root access, are just poorly developed security nightmares.
That said, I agree that it should be an option, or at least a standardized means of enabling it. As well as all bootloaders should be unlockable. But phones are more personal devices than the PC ever was, and there are good reasons NOT to push for the proliferation of standardized root access.
I can't speak to Trump's rationale, but know of at least one instance where a MOAB was substituted for the normal ordinance in theatre because it was approaching it service rated shelf life.
Explosive ordinance has a shelf life, and once they're expired, they either need to be taken out of supply for servicing, or dismantled and disposed of.