I think it is a vendor thing. They've had a yellow Sabea up until 6 months ago, then they changed the name to magenta.
You've got to remember the people that own this board ARE NOT here to keep everything within perfect conditions and to the book. They are here to run a business, and although many patrons (including myself) do not agree with selling colored, dyed, or bleached anemones, i'm sure some of the people in charge of purchasing these products from vendors are not aware of how they've obtained their unique color.
I personally think they (the people at SWF.com that purchase the products) are not aware that these are unhealthy. Remember, they are running a business, and may not have a BA in biology or may not to totally versed in proper anemone health.