At least the first quote is political and essentially casts the "other side" as an enemy rather than merely an opponent. This is not uncommon to use this strate

At least the first quote is political and essentially casts the "other side" as an enemy rather than merely an opponent. This is not uncommon to use this strategy in political speech, and it is done rather well (and probably deliberately) here, but it is not an innocuous turn of phrase. The second quote at least refers to a time when police had to play a defensive role against, once again, an enemy. This whole paragraph gives a clear vision of police having a military role (eg "fallen officers"). I didn't know that expression before, but the examples I see, (and its origin as an analogy to the thin red line) give it a connotation that is not neutral. The thin blue line is a metaphorical line between the maintainers of a certain order and a common enemy. Using this expression in the context of kernel maintenance is at least somewhat clumsy.