Diesel, I think you are misinterpreting the letter. It is not a shakedown attempt like The Rev. Jesse and his Rainbow/Push Coalition routinely runs against corporations. Jackson wants money, and if you don't pay, he and his organization will badmouth you. That's extortion.
The ACU or the other hand is offering an advertizing and mobilizing campaign. Mailings and radio ads cost a lot of money. Keene is offering to do the work, using his extensive list of contacts, if Fedex will foot the bill for postage and labor. That's just not sinister. It's a business proposition. Fedex would choose the extent of the campaign it wanted, and pay the quoted cost.
As to switching sides, I think anyone who supports Fedex in principle can still oppose its BrownBailout website, as the site inaccurately accuses UPS of seeking a "bailout."