They don't try to supress catalan independence, but violence. People on jail are there because they set fires, throw stones to police or hold some explosive substances.
A good example of why I think "terrorist" and "terrorism" communicate almost nothing other than "I think they are the bad guys". That sort of statement is ripe for debate.
On the other hand if you say that someone was arrested for arson, assault, or unauthorized possession or explosives then some objective reasoning can sort things out rather than having to fall back on an endlessly subjective debate of what is or isn't terrorism.
The phrase "hate crime" is another example of this problem. Someone being arrested for assault is pretty straightforward to investigate and adjudicate. If you also want the police to make some additional determination as to their motive and thoughts in order to make it a "hate crime" then everything is much more complicated. How about just punish appropriately for the assault and move on.
Note, I'm just talking about the use of language here, not trying to discern who are the bad guys in this particular dispute.
The word "violence" has a similar problem in spanish and catalan discourse. It has been used to describe the acts of blocking a street, moving dustbins around, or simply covering your face. The worst perpetrators of this semantic drift turn out to be catalan "extreme" pacifists, who aggressively condemn anybody who does these things in demonstrations. They are mockingly called the "dustbin protection society".
