I know it is a little late for the rejection of the central Spanish authority in their manhandling of the Catalan independent movement. But, I have had to think a lot about it. It is not that simple.
This is what I have reached as a conclusion.
First of all, independence is a right for all Peoples. Not giving a people independence is outright illegal. But there are often contradicting motives for independence.
If it is just motivated by economic growth, I believe that this is not a solid motive. If it is motivated by a wish to make a true democratic constitution, that is another matter. That I wholeheartedly support.
The right of a people to be free, is a right we should always support.
I understand, that the EU is also in two minds on what to do. On one hand, it wills to solidify the central government, but at the other hand, I understand, that there is a true respect for the will of the Catalan people. What other can you have?
The best course here is to support the Catalan people in the right manner, for the right reasons. If they want true independence, because they want more freedom, please let them have that. If it is just a matter of lack of solidarity to the rest of Spain, then I think the motives are wrong.
Then give them independence but suspect solidarity to the rest of Spain. Then the equation could be found right.
G-d bless the peace, that must come.