I would assume interdimentional beings have intelligence, which infers logic.
Where is the logic in showing up en masse to a global population and just flying around, in effect saying "Hey look at us but we're not going to reveal ourselves, so go panic for the next few months"?
This is not logical in any way.
The alternative is that they are dumb beings, here by accident and can't figure out how to get away.
Or, we have to conclude that they are man-made objects which are being deployed for a purpose, which is known by some entity or institution that wishes to remain silent about the activity.