I don't know. I am not that knowledgeable on the He 100. But the Bf 109 was originally selected over the He 112. The He 100 was a secret "redesign" of the 112 to bring it up to the then standards. The He 100 had issues especially with the evaporative cooling on the early versions. I don't think one can claim the decision against the He 100 was 100% political, but I have no clue how much politics played in the decision, if at all.
This site might answer your question.
Heinkel HE 100
Thanks,