The US gave Tehran a nuclear reactor--in the 1960s. Michelle Pilecki, who calls this "a classic example of the US digging itself into another hole," seems to think this is some kind of a gotcha moment. Doubtless George Bush was involved somehow.
Here's the thing, just because we didn't view Iran as a threat 40 years ago doesn't mean Iran isn't a threat now. The Shah may have been a sonofabitch but he was most decidedly our sonofabitch. So it's not surprising that the powers that be in the 1960s thought it was a good idea to buttress Iran's power as a counterweight to Soviet-supported Egypt and Syria.