This thread is absurd - of course in retrospect, the West should have invaded Germany in 1933 to get rid of Hitler. I should have also played the Powerball numbers 1 12 32 42 58 12 last week.
At the time, the West behaved more or less reasonably.
Not really, France could - and should in its own self intest - have invaded Germany in 1936, when they invaded the demilitarized Rhineland. They had every right to do it and - more importantly - very good odds for a successful operation, which should have been clear with the knowledge they had. Instead Hitler bluffed his way to success despite decent work by the French intelligence.
We now know the German generals were prepared to coup the Nazis if the French invaded, but even without that hindsight knowledge a strike before the German military got too strong made sense.