Re: "Aliens exist, there’s no two ways about it,"
No, I don't agree, for the reasons I gave in the post you quote. The galaxy is less then 14 billion years old, and I already told you how many stars it contains. Life took a few billion years to evolve here. It's quite plausible that it was unusually fast for us. If it normally takes 10 times as long, the galaxy (and the universe) wouldn't be old enough for it to have happened.
The thing is, although the galaxy age and size are big, the chances of life may easily be correspondingly low. With a sample size of 1, and that sample biased, we can't be sure.