I’d be a whole lot more upset and surprised if USA and China were not preparing for a war over Taiwan. It is one of the top 3 most likely sparks for war between them.
Which is not to say that it is “likely”.
Getting ready for a war does not provoke war. Both sides are doing it, we know each other are doing it, we do war games all the time all over the world and it's fine.
Freaking the public out about how the game is played is the real danger. That happened with the balloon incident too -- oh gee China spies on us? Yeah, and we spy on them too, and we've got way better stuff than balloons, and they know it.
The troops were landed on the Patuxent River, and marched a considerably shorter distance to Washington. I would also mention that the British called the burning retaliation for the burning of York (now Toronto).
But supposedly the War Department had plans in its files for an invasion of Canada as late as the 1930s.
The US has been focused on Iraq and Afghanistan and sort of neglected Navy and Air Force. The article is partly about the Marines completely changing strategy to fight China.
Finally, Taiwan preparing for war is important. They haven't been preparing seriously until recently. They have forces for power projection while they need weapons for defense. Ukraine has shown that defense against superior opponent is possible.