If Liam was actually an evil lord he would have said "castrate and enslave them" not "kill them" when talking about the pirates. Bro just doesn't know how to be a villain.
From the family he did his internship with it sounded like many families use space pirates as personal militaries against other houses so think of them more like PMCs than Blackbeard or Somalis.
In this universe, medical technology is able to keep people alive for thousands upon thousands of years. Repairing castration shouldn't be difficult or particularly expensive. Slavery just means more people holding a grudge against you (on top of all of the grudges we already see). Liam is acting like an EFFECTIVE villain, who's studied up on the Evil Overlord's Guide. The kind that doesn't make for a good foil but rather does a good job as a villain protagonist.
11. I will be secure in my superiority. Therefore, I will feel no need to prove it by leaving clues in the form of riddles or leaving my weaker enemies alive to show they pose no threat.
61. If my advisors ask "Why are you risking everything on such a mad scheme?", I will not proceed until I have a response that satisfies them.
100. Finally, to keep my subjects permanently locked in a mindless trance, I will provide each of them with free unlimited Internet access.