What the Spanish constitution says is largely besides the point on the matter of the rights of Catalonians to assemble, protest and express themselves. See Chap

What the Spanish constitution says is largely besides the point on the matter of the rights of Catalonians to assemble, protest and express themselves. See Chapter I of the United Nations Charter. The acts of internal or external self-determination such as the Scottish referendum are expressions of fundamental human rights. The significant difference is whether such acts are recognized by the international community. The sensible thing would have been to let the referendum to go ahead and not recognize the result. Instead the Spanish government uses violence to pro-actively prevent peaceful protest, and makes the situation dangerously unpredictable.