The non-racist answer in National Socialism is the offspring will be unpredictable. You don't know if they will exhibit the strengths and weaknesses of one race or the other. This is not ideal in state craft. Ideally you put the race best at leading in leadership, the best in thinking in thinking roles, etc.

Then there are real politik answers, where crime statistics can be invoked.

Then there are bad faith answers, from Kikes or stupidity. These can be ignored