Because the choice given to a voter is this:
Vote for a democrat, who destabilizes foreign countries as a matter of course, and puts their energy into rewriting a health care bill. Vote for a neocon, who destabilizes foreign countries as a matter of course, and puts their energy into keeping gas prices and taxes a little bit lower. Vote for Trump, who actually attempts to stop destabilizing foreign countries, and gets impeached and called a terrorist by everyone who suddenly thinks NATO and aggressive foreign policy is the most important thing in the world.
An actually democratic decision would be giving citizens a plebiscite, "Do you want to stop foreign intervention in X country: yes or no." It would be quite a long list, but the results of that vote would be nice to see.