This is not censorship. I choose not to tell everyone I meet about Microsoft
Windows, but this doesn't mean I'm censoring Microsoft. It just means that
I'm not gonig to advertise something I don't agree with.
Similarly, I don't approve of distros that include non-free software, so I
don't recommend them to people. I'm not censoring Ubuntu, I'm just not
advertising them. The FSF does the same thing, and IMO it's perfectly
acceptable to do so.
Trisquel takes the position that it is wrong to recommend non-free software
to its users, so it doesn't include them in its repositories. Yes, a
mostly-free system is better than an entirely proprietary one, but it
shouldn't be the goal that we in the free software community advocate. Debian
takes the position that it's ok to help people install non-free software by
giving them advice via their website and forums, and providing a non-free
repository that is available to anyone who wants it. This is why they're not
considered a fully free distro by the FSF.
I believe OP might have already known this, though, and that the question was
more along the lines of whether Debian GNU/Hurd is completely free, or
whether it is affected by the same issues that affect Debian GNU/Linux. I'd
also like to know this.