Thank you for pointing this out—willfully, uncharitably misinterpreting “thin blue line” as used by Ts'o demonstrates a severe lack of empathy for people in his position.

Jumping to conclusions about police brutality and so forth (as many here in the comments are doing) is very frustrating to see, because, in context, the intent of his phrasing is very clear to anyone who doesn't needlessly infer Contemporary Political Nonsense in literally everything they read.