1. An alliance with Nazi Germany could have provided us with excellent anti-Soviet intel.
2. Economics-wise, Germany was hard to overlook. Plenty of rich carbon resources; in the short to medium term, a significant player in the world economy up to now.
3. Better not wind up Mussolini or Franco. You don’t want Hitler jumping into the arms of some belligerent, paranoid authoritarian state. Let’s ally ourselves with Germany, so they don’t get together with their friends and make even bigger trouble.
4. Oh, and most importantly of all. Rashly antagonizing Hitler, instead of finding a reasonable compromise, would have been an unbearable provocation to such a butthurt dictator. It might even have resulted in an entire world war!