Q: But Catalans are not an excluded sex or a race, so what's the freaking problem here?
A: The tyranny of the majority, a known potential failing in democracy when it involves identifiable socio-anthropological groups as majority/minority, not just groupings of people by topical opinion.
(1) In the case of blacks in the antebellum US, such tyranny by a racial majority allowed for their permanent disenfranchisement, and remedying that has required redress in Constitutional and legislative law. (Women are a case of silenced majority; different discussion.) It required the sense of deeper democratic values beyond simply majority opinion to overcome, born of an awareness that mobs, too, are majorities that can have their victims.
(2) Catalonia is a regional ethnic minority. The Spanish constitution expressly prohibits regional votes on independence as a measure consciously and fully intended to serve as a fig leaf for permanently shutting down any thought of ethnic minorities getting out from under the thumb of the majority. It's best observed in contemporaneous political discussion under and just after Franco, as well as in very recent years.
(3) In short, the law is that minorities must submit to another, larger ethnic group in practice. Disobeying such a law is the kind of struggle for liberty any moderate should recognize as fully legit. (Think Tibet!)
(4) I.e., the Spanish Constitution has a "Slavery Clause," whose intent is the polar opposite of that of the Emancipation Proclamation. Legacy from Franco's instructions. Yuck, I know.
Q: What's with that King who, just after the referendum, did not mention when addressing the nation the hundreds of bloodied innocents who attempted to vote; many old, many women?
A: Wish I could say. There is a local gag law. He is above criticism, subject to fines and imprisonment. I can say, in general, that when someone is "mo' better equal," that system, even if democratic on the face, just like the US prior to universal adult suffrage, has poison in its democratic veins. Can't say more; but I do find the very idea of bending knee to some pampered trust fund phreak run amok with hubris abhorrent. As a general concept and with no specific reference, of course.
Catalan independence is the answer. The day Castile realizes it is not universally admired in awe, and that all on Earth do not wish to leave for heaven from the closest departure gate, Madrid (a saying of theirs), or speak "Christian" (Castilian), is the day the place grows up and has a chance of something better than a Potemkin democracy that beats innocent women at polling booths.