True, but I think that could cause issues for astronomers. Instead if seeing small points of light they could see fast moving black spots obscuring stellar objects. In a way looking like eclipses.

Give it few years and they'll get LED colors and we'll see them in "I'm lovin it" formation.

I'm sure they use image stacking to mitigate these issues.

So? Intermittent, short-termed blockages happen (jets and satellites already do this, they just aren't black).

Astronomers don't look first and then aim their cameras, and most interesting features (essentially all of them) require long exposures, which would make this problem a slight, one-time variance in brightness.