Why not? I could just as well say that someone making $50k in Arkansas shouldn't have to subsidize consular services for someone making a quarter million a year abroad. They're not really paying "full price" either given the large exemption.

The US has an interest in maintaining embassies and consulates independent of its expat population. And we often pay for whatever services we get there, so you aren’t subsidizing us.

Additionally a government should think about practicality and fairness before it implements policy. It is impractical and excessively burdensome to try and tax residents of countries that aren’t the US. Despite your stated beliefs elsewhere, it does not take very much income or bizarre situations to wander into dicey tax situations that are frightening for the expat. A small business (which is taxable in the US if you net more than about $430) can mean difficult filing in the US. I don’t earn all that much, and I’ve spent a lot of this summer working on my US taxes for no purpose other than to have them piled up somewhere, unless some IRS agent decides to make my life much more difficult.

Most people use their country's embassy approximately never.

Where they do need to use it (such as registering a birth) it's usually replacing use of a different government office, had they not lived abroad.