Well, I, for one want to know what this "periscope" looks like!
In this case, a psychic ability saved lives. That is proof enough that it can be real. Attempts to provide alternate explanations are exercises in disbelief.
It is an ability, not an artifact. "Remote viewing telescope" is someone's feeble attempt to paraphrase the explanation: "It is seeing things far away up close, like looking through a telescope."
In ancient times, a tribe that had someone with this ability was more likely to survive than other tribes, so those who proved they had this ability were honored. The followers of those who falsely claimed to have this ability were less likely to survive. It was a very Darwinian reality test.
With modern reliance on technology, psychic abilities such as remote viewing (traveling clairvoyance) were disregarded, abandoned as a means of survival.
Now, some believe in psychic abilities and some don't, but the evidence that these abilities can help humans survive continues to appear in cases like this one.