It’s not about nationalism, it’s about local priorities and local control
Critics accuse Catalan nationalists of wrapping themselves in the flag as they ignore all other problems except independence. Particularly on the left, critics question how everything is viewed through the prism of independence, when there are ostensibly much more pressing issues at hand, including social justice, women's rights, poverty, equal opportunities.
I think 'nationalism' is the red herring here. Nationalism can be a downright nasty word, often associated with Nazis and fascism, purity of race and thought. Given that some 70% of the people in Catalonia have one or more parents born outside Catalonia, that more than half the population speaks Spanish regularly and that there is not a single monolingual Catalan in the world, I find the nationalist argument hard to accept.
In my eyes, the strong current in Catalonia is not so much nationalist as it is localist, "kilometer zero". The people who live here would like to have the power to set their own priorities, to make their own decisions, and not have them dictated from what they consider to be, if not a downright hostile government in Madrid, at least one with very different priorities, say about energy poverty, business hours, fracking, language policy, and consultations, just to name some very recent examples.
Indeed, pro-local movements are gaining momentum all over the world. In towns all over Massachusetts, where I used to live, there are strong Buy Local campaigns which encourage people to buy food from local farmers and producers and to support local businesses and artisans. These towns are not nationalist, they are localist: they want to support the people in their own towns by buying local goods and keeping the money in the economy. By not buying at Walmart, they are not saying they hate people from Arkansas, or that Massachusetts citizens are somehow better, they are attempting to exert some control over their own economy.
It's not only about keeping money in the local economy. When people reject buying products made in Vietnam, China, or Bangladesh, there is no 'nationalist' derision vented toward people from these countries. On the contrary: there is concern. And there is the idea that when you buy clothing made in countries whose governments have rejected workers protection legislation you are implying tacit approval of such systems. Conversely, having the jurisdiction to insist on strong labor protection laws and then buying locally produced goods in those communities is a way to protect workers at home and abroad, and paradoxically to enact social change beyond one's borders.
Ecologists support Buy Local campaigns not because of nationalist fervor, but because buying local means less transport and a smaller carbon footprint, as well as less preservatives and chemicals since foodstuffs don't have to weather such long trips.
In contrast, take a look at the ongoing secret negotiations on the Transatlantic Trade and Investment Partnership (TTIP) between the EU and the United States. Huge multinational corporations (and countries!) want to make sweeping changes in regulations that will affect health care, food safety, banking regulations, privacy, labor laws, and democracy itself that will affect local communities from Hawaii to Warsaw. But none of those local communities will get a vote. It should be no surprise that Catalonia doesn't want to have to rely in this situation on an additional layer of a central government by which it feels poorly represented, and with which it doesn't seem to share many priorities.
It's not isolationism. The European Union has huge potential and the common currency, free movmement of people, goods, and capital, and environmental protection laws have brought huge benefits to Catalonia, which is a proud net contributor. But Catalonia must participate in forming the policies of bigger groups like the EU and the UN directly, with its own voice, and with proper representation.
What is going on in Catalonia is not nationalism in the ethnic sense. It is localism and small-countryism. There are many decisions that make more sense when made locally. The fewer middlemen between the legislators and the people, the better. The better that legislators know their people, the better they can represent them. If politicias live in the community, and have to deal with the consequences of their vote, the people have a better chance of being properly represented.
Catalans are no better or worse than any other people. But they, like any other people, deserve to govern themselves, and make decisions that affect their own communities. Only as an independent country will they be able to make decisions about social justice, women's rights, poverty, and equality of opportunities in a way that represents the local people's priorities and desires.