That's not surprising. They also see no indication that they lost in Iraq and Afghanistan or that their own population is rising against them. Why would they see indication of a tiny drone (one of many) shut down while spying over a sovereign nation, something they do on a daily basis around the world? Sheesh!
Police officer killed, 13 people wounded in car bomb in Turkey's Gaziantep, official says (Reuters)
from the article: U.S. says 'no indication' Iran shot down reconnaissance drone