GnuTLS, copyright assignment, and GNU project governance

>In addition, any such company may choose to require the FSF to stop distributing the software with portions under their copyright.
Wrong. Once you distribute code under GPL (which you have to do in order to get your contributions merged) you can't require FSF to do anything. Contributed code is under GPL so FSF can happily continue distributing it, even while suing the contributor until only a glowing crater remains.