In the US, this is a reference to the belief that members of law enforcement should be loyal folirst to other members of law enforcement and only secondarily to the law. Or at least that is how I have always understood it.
It seems obvious that that’s not what Ted intended it to mean, since it wouldn’t even make sense in this context (the debate doesn’t really seem to be about whether maintainers should be loyal to other maintainers).
A more charitable interpretation would be “we’re the only line of defense protecting something good and valuable from the outside world, so people should give significant weight to our opinions and decisions”. Which, to be clear, I would still mostly disagree with WRT the police, but it at least doesn’t explicitly endorse corruption.
The thin blue line comes from the thin red line, where a line of British redcoats held back a heavy cavalry charge in the crimean war. I've always taken it to mean that police officers consider themselves soldiers holding the last line of defence against wild enemies. Which is itself a controversial and probably unhelpful way to think about your job as a police officer.
There are many ways to state that without invoking corruption. I think Ted is telling the truth of who he is by choosing that phrase intentionally - we aren't talking about an idiot who just says stuff, he's a smart guy.
Given that "invoking corruption" is neither the plain meaning of those words, nor does it even make sense in this context, I don't think it's reasonable to claim Ted did so.
Ted Tso is an American, he was born in California, did his schooling in the US, and has worked here most (all?) of his career. As such he can be expected to know that "the thin blue line" is an idiom that carries with it a lot of connotation.
It's perfectly reasonable to assume he was aware of the implications of his words and chose to use them anyway.
I'm American, I was born in Arizona, I did my schooling in the US, and I have worked in the US for all of my career. I disagree with your assertion that "thin blue line" necessarily implies support for corruption.
And by the way, so does Wikipedia: https://en.wikipedia.org/wiki/Thin_blue_line doesn't mention this interpretation at all. The closest thing is this sentence, which is really not saying the same thing at all, and at any rate only presenting it as something "critics argue", rather than the settled meaning of the phrase.
> Critics argue that the "thin blue line" represents an "us versus them" mindset that heightens tensions between officers and citizens and negatively influences police-community interactions by setting police apart from society at large.
And yet I've never seen that phrase used other than when cops are defending their colleague who is on video murdering/raping/beating someone innocent, or by those calling for reform who are criticizing the cops covering for each other's crimes.
Even I have seen it used in other senses by Americans, and I've never been to America. AFAICT it has only acquired that sense, at least to the extent it currently has, after #BLM. Might be an age thing, that most of your cultural impressions are of a more recent date than the majority of mine? (And, say, Ted T'so's.)
And it's in a context where some group of people with special power is acting in bad faith to avoid having to follow the rules, and setting up "us vs them" arguments to do so!
