You also can't just ignore the Constitutional rights of the 3M Catalans who didn't vote yes and move forward unilaterally with a declaration of Independence. The Constitution holds the entire government accountable—there is no "dialog" to be had outside of changing it.
The Catalan Parliament didn't even have the votes to change their own Statutes of Autonomy!
https://en.wikipedia.org/wiki/Catalan_independence_referendu...
The "Yes" side won, with 2,044,038 (92.01%) voting for independence and 177,547 (7.99%) voting against, on a turnout of 43.03%
Calls for dialogue and negotiation, which lasted until the very last minute, failed.