To me, it seems your characterization of "true point" adds layers of abstractions such as "nationalists" and "right-wing movements". Sure, you're writing text that can be considered "correct" but it actually doesn't help people understand it better.
Would it be clearer for outsiders to look at it as a mostly economic independence? For example ... to use a (tortured) analogy, imagine that California wants to secede from the USA because citizens (especially the wealthy ones in Silicon Valley) feel too much of California tax dollars prop up poorer non-performing states like Mississippi and Alabama. Also, the corrupt USA federal government is spending too much $$ on unneeded military expenses like tanks and bailing out Wall Street. Therefore, California feels its unfair and wants independence to run their own affairs. To parallel a similar confusion of the "true point"... if we simply describe the independence movement as "State Secessionists fighting the Feds", it adds abstract labels to the opposing sides but doesn't really explain the situation.
Is there a more primary undercurrent to the Catalonia independence movement than the economic analogy above?
(One example of a Catalan pro-independence answer talking about economic grievances and corruption: https://www.quora.com/Why-do-many-Catalans-want-to-secede-fr...)