The article nominally is titled "How Radical was Rachmaninoff?", but my read sounds a lot more like the author is overly obsessed with questions of being up-to-date and fashionable and is struggling with the idea of liking something that isn't (or wasn't) following the latest fashions and is having some cognitive dissonance as a result. As a bonus some fashionable cognitive dissonance is signaled at the end about whether it's OK to enjoy the work of someone who dies long before their nominal country of origin does something the author doesn't like. (I say "nominal" because Rachmaninoff died two "countries" ago.)

To which my reply would be in essence, stop worrying about "fashionability". Here in 2022, you can have any number of community's fashions, and any amount of work being done in any number of older styles. Don't look to some particular community to tell you whether it's OK to like something. (And I really wouldn't recommend looking only to what currently passes for academic "high" music.)

And as for the latter, give up liking anything if that's going to be your standard. Wait long enough and the descendants of every culture currently existing is going to do something you don't like. Might as well get ahead of the curve and just reject everything now because someday someone somewhere is going to do a bad thing.

Reject your inner high school. Like what you like. Dislike what you dislike. Stop waiting for other people to give you an approved list of what it's OK for you to like.