It doesn't seem logical to think we're the only life forms or that Earth is the only planet that sustains life, I agree with you.
I few up with a healthy appetite for sci-fi and the ethos that just because it can't be explained it doesn't mean it can't be.
I don't know if the government are involved, it's possible of course, but I feel it's also possible that there's other live in the universe and that they are here scoping things out.