Personal politics are seeping their way into nearly everything…
The only thing political about this is that some people would rather not think about the consequences of human actions. It's intensely political to say that we shouldn't care about or raise awareness of human-caused extinction.
This isn't even politics per se, just feel good activism, the "I'm helping", while doing absolutely nothing that helps in the topic). Equivalent to thoughts and prayers.
"...dividing its pages between offering background on the real-life animals - and the reasons for their disappearance - and providing versions playable in D&D 5E and other RPGs."
Is learning why animals are no longer around controversial? This book seems like it does in fact teach facts and isn't doing absolutely nothing as you put it.
What part of any of this effort improves either the gameplay of backers or the state of conservation?
There is no need in any edition of the game for another book of 100 monsters. I already have hundreds of CR <1 small birds and mammals, and similar numbers of herd animals and apex predators. Even with "reimagined powers" it takes about 30 seconds to throw an extra power on a monster even in extra crunchy editions of the game.
My major question with any gaming product is what fun does this bring to my gaming table? And I don't see any fun that it'll add, at least not to my game. Most of what I see is some decent swag and some indulgences someone could buy for their feelings of guilt at conspicuous consumption in the hobby.
So... your issue is that someone... somewhere... has written a book... including a cause they believe in?
This doesn't even strike me as activism, unless you're uncomfortable with looking at a Dodo illustration in your D&D campaign. This is a book with extra monster ideas, some of which are inspired by animals you will never see. Even devoid of empathetic value towards those dead animals, you gotta admit it's pretty metal to fight an animal that doesn't exist... anymore.
If using extinct animals as inspiration for monsters is a crime, then Gygax should be prosecuted first: https://forgottenrealms.fandom.com/wiki/Saber-toothed_tiger
And deeply stupid. Don't like a change? Ignore it. Don't like something that's included in RAW or official sourcebooks? Ignore it. There are no Correctness Police at your table, you can do WTFever you (and your players) want. Want obsidian-black always-evil Drow? Go nuts, nobody cares. Think that's horribly racist? Make them purple and not alignment-locked. Hell, make them albino. No one will stop you. Most of the politics-related changes have been really, really easy to just house-rule out of existence, and most of the things that bothered people about older editions or settings are similarly easy to modify without having to extensively change other parts of the system. It's just a bunch of noise that barely matters at all.
Don't like this extinct creatures manual? Just... don't buy it or use it as a source for your games then? It's so easy.
And yeah, dinosaurs and mammoths and shit have been in D&D basically forever. Some of its major influences were "lost world" fiction and Conan-style prehistorical fantasy, so of course those are in it. D&D doesn't draw primarily from e.g. Tolkien-style high fantasy where dinosaurs and such might seem out-of-place. A source book for extinct animals for D&D falls solidly within the spectrum of "totally normal D&D stuff".
- The authoritarian Wizards/Hasbro ownership that wants to commercialize and streamline the image of D&D
and
- The ass-wack community of people playing who have no intention of changing the way they play
Neither of these parties are particularly wrong, but they'd be better off without each other. Hasbro should focus less on appeasing older wargamers and let their streamlined product serve as an introduction for younger players, and community shouldn't worship WotC for repeatedly failing them.
At the end of the day, the best solution is like you say - dust off your favorite edition rulebook and write everything from there. It's all just fantasy, you can mix-and-match whatever you want. However, the best fantasy isn't passive or ambient writing. It's thought-provoking stuff that uses powerful analogies to tell a powerful story. Shying away from real-world inspiration or conflict is the equivalent to failing as a fantasy author (in my book).
Currently the extinction rate is 100-1000 times higher than the normal background extinction level. [1]
This is just drawing on reality for inspiration. Not some sort of political credo.
Too many people conflate "worldview" and "politics."
By this comment, I assume you mean the authors are pushing a specifically political agenda, intended to change government or influence government policy.
I'd love to hear you explain how that is the case.
Such as protecting endangered species?
The government is not the only way to protect endangered species.
You used to not be able to use the word D&D when promoting your 3rd party product, only the term 5E. I wonder if this has changed due to the recent SRD change. I thought I would like that, but this initially confused me as I thought this was an official D&D product.