Like I say, I'm all in board with accepting that aliens are likely to exist, that's the easy part of my list. And accepting that aliens can travel vast distance

Like I say, I'm all in board with accepting that aliens are likely to exist, that's the easy part of my list. And accepting that aliens can travel vast distances is also plausible, we just need to make them very technologically advanced in order to do so in reasonable time scales. And then possibly these very advanced aliens want to come to earth specifically out of curiosity or something? But the problem is with each premise you're making more assumptions, and as you get further those assumptions start contradicting each other. The aliens aren't making their presence known so clearly they want to hide in some way. But these super advanced aliens keep on getting spotted, so maybe they don't want to hide, or they're not that good at hiding? So maybe they don't have all that good technology? But now how do we get them to fly between solar systems to make the start of the theory work? And the further down the list you go, the more assumptions start to contradict each other, or become a step to far. But all of the assumptions are necessary because otherwise there's a gaping flaw in the whole idea.