Was Dutch a short-hand for being treacherous for J. Lee Thompson??

In Ice Cold In Alex we have an Afrikaans (a Dutch language) speaking person who turns out to be an enemy agent.

A year later, in North West Frontier, again directed by J. Lee Thompson, we have a Dutch East Indian half-caste called Van Leyden who, in a very similar plot device, also turns out to be an enemy agent.

I wonder if Thompson had some bad experiences in his life with Dutch speaking people, like having his proverbial school milk stolen as a child?