Im aware of Czech history, being one myself, the fact is not so much they lost their nerve but they were sold out by both their so-called allies the French and British who were trying to get peace with honour and got neither (to quote Churchill)

I doubt the Germans would have been repulsed that easily, despite the border fortifications - but it probably would have slowed them down.

the overthrow of Bokassa, Idi Amin etc are other examples of justifiable military interventions - simply for humanitarian reasons.

I wonder how many others supported Saddams right to nuclear weapons.
certainly gulf war II and III would have been different.