I strongly recommend having a look at the mailing list to get some context:
https://sourceforge.net/p/sbcl/mailman/sbcl-devel/thread/CAF...
and
https://sourceforge.net/p/sbcl/mailman/sbcl-devel/thread/CAC...
This will certainly speak to some people taking part in some of the more controversial discussions taking place on HN recently, to put it mildly.