One paragraph there says the banks need to sell them so they can invest in other things... Do I smell the banks realizing "oh shit, we're holding a bomb, we need to convince some other fool to take it before it blows up...".
The real reason they will be doing this is this is what they do in general. They don’t hold on to huge amounts of risk with predictable returns (because it consumes their operating and regulatory risk capital inefficiently) they will instead find buyers for that risk, which frees up capital they can then use on their next thing. That basically gives up some of the long term, low return, low volatility risk for shorter term, higher return, higher volatility risk.