Fair points.He may indeed be overstating, but those two examples are poor. Hungary's 56 revolution lasted 11 days. There was no time for the US to give weapons had we wanted. The Prague Spring was never an armed conflict at all; it was a diplomatic/intellectual affair for months until one night the Soviet troops came in and took over.
Not to mention the fact that neither country shared a border with a NATO country, though that's tangential at this point.
Those two episodes say nothing about American policy because they were over too quickly for Americans even to have gotten involved. No matter what American policy was, it would have ended the same.
That said, the current arming of Ukraine -- at least in degree -- is unprecedented for America. Given that, it is hard to say what any former American president would have done if that person could have been transported to 2022. I suspect the policy would have mirrored Biden's but maybe Reagan would be a little more cowboyish.