In the comedy movie, Galaxy Quest, there is a scene in which the characters arrive on an alien planet in a landing module. One of the characters opens the door, whereupon another character objects, pointing out that the atmosphere might not be breathable.
Of course, the overwhelming odds are that on most planets, not only is the air unbreathable, but the gravity might be fatally strong, the radiation extreme, the "sunlight" could be unsuitable for human eyes and skin, and so on. There are many factors that could adversely impact us.
Likewise, our atmosphere (and other factors) could be unsuitable for alien visitors from other planets. Yet, many reports of extraterrestrial beings emerging from their transport craft (or landing modules) indicate that they find earthly conditions to be conveniently survivable, despite the odds against.
This would indicate that such creatures are either purposely designed (mutated, or otherwise) to survive on our planet--or else, that they are already native to this planet, and do not come from elsewhere.
This makes it plausible that, if these reports are accurate, nonhuman intelligent, technological creatures are native to earth, and that perhaps they reside under the sea.
There are so many convoluted reports that I find it impossible to analyze them in any coherent fashion. That is why, until some definitive, concrete evidence is made public, I have backed off from this topic.
