As Carl Sagan was fond for saying, "extraordinary claims, require extraordinary evidence".
To be blunt, the holes in that (Youtube/UFO) argument you could could drive a Mack truck through.
In the age of millions if, not billions, of image capture devices, you'd think someone would have caught a nice clear picture of ET and despite this BS being debunked time and time again, still there some stalwarts who believe similarly to those who think the earth is flat...
I have seen many trained professionals mis-interpret parallax, and mistake Venus as a "tracking" light in the Sky.
Expert opinion and the opinion of an uninformed "expert" are often vastly different. It doesn't take a lot of crtitical thought to work out who the snake oil salesperson is.....
Do I think there is life elsewhere in the Universe? ...well yes...could be anything from bacteria to sentient beings.
but..as Douglas Adams once wrote, the Universe is *really* big....hence as for aliens are hovering around the earth in UFO's...the word delusional comes to mind.