"You need to read history to understand the situation."
That is true if we want to analyze the question of whether or not Catalan "should" be independent from Spain, a question so murky and shot through with political philosophy, theory, and pragmatics that even two sides that stipulate all the same facts can come to different conclusions.
But for what johnnyfaehell was really getting at, which is a tactical and/or strategic analysis of the effectiveness of the moves the various sides have been making, we don't really need all that, we just need an understanding of human nature, with at best some slight elaborations for the slight deviations in local conditions.
I personally have no great opinion about whether Catalan should or should not be independent. Distinctly from that, though, it is fair to observe that Spain has handled this quite badly. While there is probably no solution in which they completely smooth things over, they have certainly taken multiple moves that are very clearly the simple, intuitive things that our genetically-imposed tribal political sense tells us to take when people challenge our rule, and which work (to some degree) in a tribal context of 100-ish people [1], but which at this scale were basically guaranteed to massively inflame the situation.
[1]: Albeit in a way that many people here would probably find generally unjust. The Big Man in the Tribe basically just telling a couple of rabble-rousers to shut up, and if necessary, getting some of his supporters to rough them up a bit to remind them who is in charge, "works", but a lot of us would find that fairly distasteful, because while our genetics tell us to do that, civilization requires other tactics in order to hold together. Scaling up that Big Man's action to a region breaks in multiple ways; for instance, if Catalan perceives itself as a separate tribe, then the "rough them up a bit" phase doesn't register as an internal tribe spat with our genetically-programmed politics, but warfare between two tribes, and that prompts a radically different response.