The United States was founded on secession. It didn't have to be violent, but it was. Whose fault was that? Was it the United States' fault for insisting on more local governance? Or was it England's fault for ignoring the consent of the governed?
In 1991, when Ukraine and Belarus declared their independence from the USSR, things did not end violently. They were allowed to exit the union peacefully. The Soviet Union dissolved without further violence.
Of course, there was plenty of past violence the Soviet Union had used since 1922 to keep Ukraine under their control. This included the orchestrated famines in the 1930's which killed around 4 million Ukrainians.
But why is it so clear that places like Ukraine, Belarus, Latvia, Lithuania, and many other countries were justified in declaring their independence from the USSR?
Was it the fact that they had been independent countries at one point? That would suggest that Catalonia and Kurdistan are equally justified in demanding independence, based on their historic sovereignty.
Both referendums place these secessionist regions on a collision course with their central governments and the international community, increasing the probability of conflict…
Roughly a third [of secession movements since 1945] have resulted in violence. Indeed, some claim that secessionism is the chief cause of violence in the world today.
Isn't that like saying, the best way to avoid rape is to say yes? Demanding autonomy may bring violence upon you, in the same way that resisting a sexual advance might do the same. But the violence was not caused by either victim.
According to Griffiths' book The Age of Secession, between 1915 and 1945 the fewest sovereign nations existed on Earth since 1816. (This was also the fewest since well before 1816, but that is how far back his studies goes.)