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Imagine a whole article about high-energy astronomy never even mentioning plasma or synchrotron radiation.

Trotted out "hot gas", though.

I am mistaken: "plasma" appears once in a hidden caption I missed first time through.

I'm not sure why you're bringing up synchrotron radiation in particular. Although it's important for some sources, it's not driving the majority of what is being seen here. Comptonization is important for active black holes. The radiation from the milky way has strong emission lines - it's not a synchrotron spectrum. Mostly thermal emission is emitted from clusters of galaxies. There are a lot of different emission processes to consider in astrophysics.

If, as you say, there are a lot of different emission processes, why only ever mention the, by far, least interesting? Elsewhere in science exceptions are interesting. The unexplained is interesting.

Lev Landau is reputed to have said, "Cosmologists are often in error, never in doubt." Doubt is productive.

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