Nope. Not a cop. I said less likely to face oppression from royalty. He is clearly aware of the inherent unfairness of the system. On the other hand, the gate guard griffin was clearly in the position of law enforcement and look how he reacted to Virginia when she showed. It's a bit like cops from our world facing a Black man with a cell phone and shooting him twenty times. I do not know how that would have ended if Liam had not intervened but I am, shall we say, not eager to bet a thousand dollars on the outcome being harmless and without injury.
Liam, I suspect, is in the position of being immensely privileged but not having the leverage to intervene directly. He may be helping the rebels because he believes he can shape the situation to reach a less destructive outcome than open warfare. It would be unsurprising if saddening if the rebels were much less optimistic about that and were preparing for violence anyway.