I think we have a basic misunderstanding of private vs public ownership. When we all own it, you can't just do whatever you want like build a house, but withe proper permit, you can use it. If it was private, I could never do something with what you owned.
In the case of public ownership, I don't own it though. The entire public does. I'm willing to say "the people own" these telescopes, but that isn't what you originally said. You said "as an American, you own them" which isn't true.
Ownership rights and various kinds of access rights are not identical and often conflated.
For example, if I own a water well, I don’t necessarily have the rights to do whatever I want with it. Some jurisdictions might let me pump out as much water as I want, but even those will punish me for blatantly polluting it (one would hope).
What some people think of as something akin to “total ownership” — completely unlimited access — would be tantamount to putting one’s “rights” above everyone else’s. Even dictators usually have some limits on their power, whether by laws, norms, or geopolitical pressures.
I would say that in your example, the well is really two things: the water table (which you don't own), and the pump you use to draw water (which you do own).