The true resolution of military hardware is normally highly classified. I worked for a long time with military satellite imagery. Many times we'd have a photo of a facility or something with decent resolution. We'd ask if they had a higher resolution just because more detail is always better, the answer was almost always "yes, but you can't see it." Why? Because I was given enough to do my job, if I needed the higher resolution it would require jumping through a ton of hoops, writing a justification as to why I had "need to know", etc. If I saw the higher resolution image, I'd know exactly how good the cameras on the satellites are. Our adversaries would also have a lot of interest in knowing the capabilities, which is why it is such highly protected info. I had all the clearances you can think of but I still wasn't allowed to see it (for classified info you need both clearance AND need to know. I didn't need to know). Your FLIR image above is a nice resolution- it's also about 40 feet away. The objects in the released FLIR images are, at minimum, many thousands of feet (perhaps miles) away. Does the military have high resolution footage similar to your image? Probably yes. Will the high rez photos be released to the public? Probably not. You can get of sense of what I'm talking about by thinking about GPS. The public has it, everyone uses google maps to navigate. The GPS you have is accurate to within a few yards. The GPS the military has is orders of magnitude more accurate than that. Is the military going to let you know how accurate GPS really is and give you access to those capabilities? Not any time soon.
What we can tell from the images (especially the tic tac video) is that there are no control surfaces. I think the U.S. has far better tech than either Russia or China, so if it is man-made, then it's ours (I was just reading an article the other day about how China's new "stealth" fighters have made a habit of having their engines literally fall out during flight). If it is ours, it's technology that's 100 years more advanced than what we have. I don't think we have that level of tech yet. So that leaves a third, extremely strange option.
As for the argument that they couldn't stay hidden all that long- why not? The ocean is huge. Not too long ago a jumbo jet crashed in the ocean and we still haven't found it despite satellites all over the world, telemetry data, and hundreds of ships looking for it. Whatever these are, it seems there aren't that many. Also, if some of the exotic theories of how the propulsion system works is true, then that also explains why they aren't seen. The AATIP Chief (and UM Grad!), Luis Elizondo, has hinted that it involves time dilation and the objects capable of moving at relativistic speeds (he indicated that's about the extent of what he can say due to his NDA). That would also track with what CDR Fravor described- the object seemed to mirror him cautiously, then when he decided to approach, it moved vertically and suddenly disappeared. The radar returns corroborated this- it was at one place (where Fravor and three others saw it), then it appeared 60 miles away in an instant. If they can move at relativistic speeds, then you wouldn't even see a blur.
And lastly, let's cover some assumptions that I think everyone will agree with. It is a statistical certainty there is intelligent life elsewhere in the universe. Most people would also agree that it is a near certainty that humanity will advance computers to the point where there is true artificial intelligence. Elon Musk already developed a rudimentary computer/brain interface and we haven't even scratched the surface there. Now let's say another civilization, has oh, say a 1000 year head start on us for tech development. That's low end, it's possible there are civilizations 10s, if not 100s of thousands of years older (modern humans appeared around 200,000 BC, just try to imagine if humans had developed agriculture around 100,000 BC instead of 10,000 BC). A difference in 1000 years is basically nothing on a universal scale, but it is almost beyond our mental comprehension to think about what kind of tech we would have in the year 3000. Safe to say that through the combo of artificial intelligence and a human/brain interface, humans could be virtually immortal and upload our consciousness to some kind of internet. Again, most people assume this will happen eventually. Once that occurs (the "singularity" as it is often called), time is basically immaterial. Who cares if it takes 1000 years to travel at sublight speeds between stars, you likely wouldn't even notice. So there doesn't even need to be any sort of faster than light technology (as far as we know, physics doesn't allow that) for extraterrestrial visitation, it just requires another civilization to follow a similar technology curve that most assume humanity is on.