Proof of stake lacks the security properties of proof of work, because casting conflicting votes is free.

If a product can't be secure without using more energy than most countries (and if that security is considered to be important), that product is garbage and shouldn't be allowed to continue.

Unfortunately it’s not up to your personal opinion if things are “allowed to continue”.

A fair comparison with Bitcoin alternatives reveals it is net more efficient than the things it’s replacing (petrodollar warfare, giant payment processors, etc).

The US dollar is only secure because of the US Military.

If a product (US Dollar) can't be secure without spending more money on defence than most countries combined, that product is garbage and shouldn't be allowed to continue.

Thats with discounting the other costs, such as the loss of human life, when the military decides it needs to invade somewhere to make sure its 'enemies' can see how big its stick is.

Isn't issuing conflicting votes, if proven, costing people their stake?