It is true. And yes, using the year is more politically correct given the current culture and climate.

I think the question of naming is less of origin, and more of cultures and what offends someone. Back when and where I was a kid growing up, people were mature enough to realize that terms like "Spanish flu" or "Chinese coronavirus" weren't condemnations of Spain or China, and we somehow never saw violence or offense over these sorts of things.

They were neutral, factual descriptions. And yes, factually, the Spanish flu was first widely reported in Spanish newspapers.

In the US in 2021, it seems like racial tensions run high, and these sorts of thing DO lead to offense and violence.

It's an odd shift, but not an unreasonable one. A big part of this has to do with intention. With COVID19, the racial terms were intended to be offensive by many who used them. Whether someone is trying to insult you goes a long ways to whether you might reasonably feel insulted.

Have you heard of anyone being insulted by "Spanish flu" prior to the e.g. 1980?

As a footnote, a more subtle way to play this is to code switch language based on where you are. In China, I don't get offended by people calling me fat, whereas in the US, I do.