Patellar breaks people. You fall in line or get fed to the dogs. While its one man who is "at the top", his power is maintained by the support of his people; it is what sustains him. The manipulation initially makes you subservient and submissive - a perfect little puppet waiting to be puppeteered. Eventually that turns into undying devotion; this is when he can truly use his people for anything and everything.

Patellar's slaves have been broken into and, essentially rewired for his proclivities - them even encouraging and engaging them sometimes. While we don't know for sure, we can assume that the other slaves also had similar journey to becoming Patellar's 'helper' as Thommy's.

What makes Thommy different then? Autonomy over one's own actions is lost in a master/slave dynamic. Thommy always voiced his opinion even when he got repercussions for it from Patellar. I think the continued dependence on Thommy by Patellar was because while thommy might oppose to Patellar's ideas, he knew Thommy was more than just submissive, he was full of blind devotion and loyalty -internally Thommy worshipped Patellar.

At the start of the movie, he is full of rage towards Patellar. Over the course of the movie, he is swept off by Patellar and forgets that ember of rage within him. Even during the attempted murder of Patellar, he is not entirely committed to the idea. That could've been his way out - a stable job and a dead rapist. But he did not want it. I'm not saying he secretly enjoyed being demeaned by Patellar; I think he was manipulated into thinking "what am I without Patellar?". His whole life revolved around him. Patellar striped him of any extensions of his identity that weren't about Patellar. He cultivated a dependency. Death of Patellar's is what makes him realise how in deep he actually was.