I didn’t read the whole 1977 article, but from the excerpt I took that Hitler’s success was enabled by his eventual opponents’ weakness. I don;t know if Buchannan is referring to German and Austrian leaders, or if he is including the likes of Chamberlain and other foreigners.
What bothered me was Buchanan describing Hitler like a giddy schoolgirl would describe her favorite popstar and then suggesting that Hitler should have been left alone.