My take away (and granted I had to stretch for this, the movie does not do a good job portraying it).Yeah, I didn't really understand the villain's motivations beyond revenge for his father's death.
1) Parents killed by Spectre, swears revenge.
2) Obsessed with poison, probably from parents profession and upbringing.
3) In pursuit of Spectre and new poisons, makes the connection to Heracles (the how of this is probably the biggest mystery considering how secret it is....but then again he managed to poison all of Spectre so ???)
4) Now realizing the theoretical power of government and what could be done with Heracles.... he decides to take it for himself. Ultimate control so he can never be abused again (and perhaps believing he will stop abuse in the world to).
So that's what I went with, but yeah agree the villain is paper thin but at least was interesting.