Matt Dillon was never blacklisted. His commit rights were revoked. That means he could not directly commit to the FreeBSD tree (CVS in those days) and would have had to give them to a committer. There is no such concept in the Linux kernel -- only Linus can commit to his tree and he has a human tree that feeds him patches. In other words, Matt was in the same situation as every other Linux developer other than Linus -- except that he could have submitted his patches to multiple people if he chose.
The reason this was done, reportedly, was that he was not following the rules and was treading on too many toes. (Incidentally, his rights had been removed once before, and restored; this time it was permanent.) I don't know the merits of this claim, but obviously when you have a centralised repository you need to play nice with others. One could say that this is a merit of the Linux model. Indeed, Matt's DragonFly BSD project now uses git for source control -- which is a testament to the success of Linus's style, since git was written by Linus for his exact requirements.