The Texas war for independence had little to do with the Mexican American war and seizing California—and all those elections—Russia had election too in Donbas and Crimea too—how honest were they? How honest was the 1959 election in Hawaii?
No, America is no saint—few big nations are. Ask the people of Northern Ireland about “Free Elections”.
The Spaniards in California were quite notorious for using the Indians as slaves, btw. Not that we Anglos treated them a whole lot better, but at least they weren't forced field labor.