Earlier quoted context omitted.
Ummm, Crimea has been majority ethnic Russian for over 100 years, Ukranians weren't even the dominant minority in the region for most of the last two centuries. You really should learn some history before commenting
"Ethnic Russian" != "Russian", though. No matter what ethnicity, they were citizens of Ukraine. And I completely deny that Russia has the right to speak for ethnic Russians of other nationalities, and to invade their countries on their behalf.
Prior to Russo-Turkish war Crimea was a part of the Ottoman Empire, after Russia won that war it conquered Crimea and absorbed it into the fold in 1783. Crimea has not been a traditional part of the Ukraine since before the existence of the United States of America.
Failure to grasp reality does not change the fact that a Crimea filled with ethnic Russians, host to Russia's Black Sea Fleet, in a city founded over 250 years ago by Russia, which holds extreme strategic importance to the nation could never be allowed to fall under the sphere of NATO.