As others have said, the flag or the LEM base unit cannot be seen with any current Earth-based or Earth-orbiting telescope.
But they did plant laser reflectors at those sites which can be “seen” by bouncing a suitable laser off of them.
The challenge for any semi-sensible person is that once the conspiracy loonies have planted doubts in your mind, what will it take for you to become convinced of the truth?
Suppose in 5 years I show you a shot taken by the not-yet-in-orbit super-Hubble which NASA is currently building. That shot shows the LEM and some other equipment. What’s to say that’s not faked too? Any evidence a layman might ever see has to be provided through high-tech channels and is potentially subject to fakery by the forces of evil, assuming such exist.
So in essence it becomes a contest of faith. if you trust the conspiracy nuts, then you can’t trust anything you don’t have direct personal experience of. If you trust the system and your common sense, you’ll recognize this conundrum and not fall prey to the conspiracy nuts.
Has anyone ever been to the South or North pole? How do you know? Answer: you don’t, except by taking other folks’ words for it.
I’ve never seen Singapore with my own eyes, and for all I know, every purported photo of the place is really Bankok. But you know what? I trust that Singapore really exists.
Just like I trust the Apollo 11 really occurred as NASA said. I watched the live video that day as a kid and I saw men walking and dust flying & falling in low-G conditions. Conditions not simulatable on Earth and far beyond the computer technology of the era to generate as a video special effect.
One of the fascinating side effects of the internet is that real news and facts by real reputable agencies, be they government or academia, or industry, or media, tend to not have long lives, whereas the pet theories of crackpots live forever.
You can’t retrieve the 1969 headlines and engineering studies, but you can retrieve the nutcases’ rantings. So Google would have you believe that 9 out of 10 sites that have an opinion think it’s fake. But that’s only because the thousands of examples of real data have fallen off the back of the history curve.