Earlier quoted context omitted.
I agree with you on stuff like schools, firemen, and healthcare. But it's a different calculation for a head of state. When 300mm people look to an individual as a leader (rather than 3mm people) there are 100x as many threats to their security via disgruntled citizens, crazy people, etc, so physical security has to scale. It's like saying, "why does the mayor of my town not need the same number of secret service as…
Rather than spending money "defending" your leaders, wouldn't it be better if you addressed the issues and actually figured out why people want to cause harm to their leaders? You know, many developed countries don't even have a security force for their leaders, and for example, the ex-Prime Minister of Australia went jogging all the time by himself, in whatever city he happens to be in.
Here's why people try to assassinate politicians:
#1 They're nuts (Hinkley, Czolgosz, Squeaky Fromme).
#2 They have some reason for doing so (Gavrilo Princip, Booth, probably Oswald).
There. Figured it out. As it happens, there are probably 100x as many nuts in the US as Uruguay, and probably 10,000,000 times more possible motives to kill the head of state/head of government/commander in chief/international celebrity who holds the US's highest office. Now you try and fix those two things.