Big difference between some dudes testimony and hard irrifutable evidence. A few officials can say whatever they like. Until you get hard XCOM level evidence in front of a public hearing the government won’t confirmed shit.
The real reason ayylmaos will never be confirmed until the hand is forced is that a huge majority of the global population ascribe to a religion absolutely incompatable with the existence of extraterrestrial life. Sentient non-human highly technological extraterrestrial life at that.
The moment it is confirmed there will 100% be mass panics by religious fundamentalist that space is inhabited by demons or whatever rationalization they pick to ensure their beliefs are still unquestioningly correct and the god given truth of 2000 year old scripture is maintained. In some areas like the USA bible belt or the middle east this will be devistating and cause actual long lasting damage to global society at large. Its a bottle of lightning all the space age nations of the world have deemed not worth opening for societal and economic stability. If these people really have the goods to back up their talk, they will be epstiened unless they take the upmost caution.