He hasn't been silenced. He still has internet access and the many publishing platforms that affords him.
He's been dissociated from a role in an organization.
If his ideas so clearly stand on their own, then he should have no problems. What he will not be doing anymore is acting as a direct representative of the organization.
He's being branded as an insensitive twit who's pattern of behavior has showed no signs of attempts to change, understand or really engage with the criticism he chooses to attract, and has finally broken the camel's back and this is the result.
Edit: have you ever witnessed something where all you could think while watching it was "Guy, just shut up, you're doing nothing but hurting yourself by talking."? Now imagine that instead of being some guy on news coverage it's someone who's seen as the public face of your organization, he has a history of doing the same thing and you have zero faith that he won't do it in the future.
Even were he to turn out to be an incredible coder and lover of open source, I also wouldn't expect the FSF to hire David Duke as a spokesman because the combination of two unrelated advocacy positions would be a distraction for both.