Black helicopters without FAA-required running lights are regularly used by the drug interdiction office DEA. In addition, most US Army helicopters (such as the Black Hawk) are finished in a very dark chocolate or olive matt paint. With the progressive development of night vision goggles, the need for helicopters to be lit when moving as a planned formation has been reduced.
See also: TACMAR
in short, any farfetched theory concerning any government or other conspiracy, can be espoused by either those of right or left wing persuasions.