Inaccurate. Ostensibly the troops were there to protect the massive amounts of war materiel donated by the Allies to the Russians for use against the Germans.
Why American (and other Allied) intervention is considered shameful is obscure to me. The Bolsheviks took power with the proclaimed intention of overthrowing every other government on the planet. Essentially, they declared war on the rest of the world.
For that matter, the intervention was an international effort in the very best traditions of the later UN. Over 150,000 troops, with the US providing less than 10% and by no means dominant. The author should have loved it.
BTW, we also had troops in the Archangelsk region.
You might want to reread that paragraph for context, because she's using it as an example of US/Russian cooperation, from what I can read.