Bank of America just called to give me an update. They explained you needed to be invited, etc. but as a gesture of good will they would “meet me halfway” and give me 2,000 more points. I pushed back, got him to visit
https://www.amtrakguestrewards.com/cardholderholidayoffer, explained that that site is run by a company with legal and financial ties to this card, how it contains terms and conditions that were very clear and presumably reviewed by lawyers, and that while they may have wished they included terms about needing to be invited or wished they had made this page something you only saw after you logged in, they did neither of those things and I would only accept all the points as the fair and appropriate outcome. And he said yes!
So the remaining 6,960 points will post to our account in next billing cycle. I am going into a meeting now and can’t talk but we won!