They exist to protect US Politicians. They are servant soldiers. They do what they’re told. Period.

That’s not how your state is supposed to work. I’m writing this from Russia, which makes the situation kinda funny, but they are not servants and presidents are not masters.

Presidents can’t make some decisions. Risking their security this way would endanger the state simply because it’s a disruption if a president gets killed or kidnapped or spied upon or their orders falsified. The secret service is subordinate not to presidents’ whims, but to an institute.