1. The number of ex-Crystal cruisers who (a) know about Cruise Critic, and (b) who have also gone on a recent Seabourn cruise, and (c) who bother to comment on their cruise here is vanishingly small compared to the total number of ex-Crystal cruisers. Of course you will hear complaints (after all, this is called Cruise Critic), but that is a skewed population and most likely not representative of the totality of cruisers who don't post comments here.
2. Attracting new passengers to Seabourn seems essential for this cruise line to survive. The large bolus of ex-Crystal cruisers who have been abruptly injected into the pool of possible new clients for Seabourn is incredibly fortuitous. It would be malpractice for Seabourn not to make an aggressive move to attract them.
3. I can understand that some faithful, longtime Seabourn cruisers would feel somewhat betrayed by newbies being able to skip the line, but this will only be an issue if Seabourn provides an excellent cruise experience, otherwise it will be one-and-done for those newbies at Seabourn.
4. If one has to wait a day longer for laundry, or has to put up with a slower internet, that may be an acceptable price to pay for securing more revenue for Seabourn and, thus, allowing it to continue as a financially viable cruise line in the future.