It is a common misunderstanding that freedom of expression is an unlimited freedom. It isn't. You can't publish clearly racist manifests, etc...
But this is not a matter of free speech. It is a matter of breaking the law.
Expressing anything (not ilegal) in a peaceful way is ok.
Who has said/or done anything against that?
This type of expression can't in any way be describe in a negative way like you are suggesting. Its not hate speech or screaming fire in a movie theatre.
Screw the law, this is about rights!, laws can be made to say anything but it doesn't make them right. Stop looking to Law makers or the state as some unquestionable deity.
The right of peaceful free expression trumps all laws!
Freedom of expression is binary: either there is or there is not. "Hate speech" is b/s. Hate is as legit as love.
That said, who does not want be governed by Spain or anything else is fully entitled to pursue his intention with any measure necessary.