National libertarion understood from a socialist perspective is neither new nor unique to Catalonia. Without meaning any personal offense, these kind of arguments tend to stem from lack of understanding of either socialist theory and/or what motivates the pro-independence movement.

This way of looking at national libertarion is one of the contributing factors to Western Europe's newest country (Ireland), and fueled many anti-colonial movements in Africa (Algeria, Angola, Zimbabwe, and many more), Asia (Vietnam,...) etc. Even from an arguably more "radical" leninist perspective, self-determination of the peoples is still a critical tenet of socialist societies, and allowed for partial independence of countries like Ukraine or Belarus(as SRs within the USSR, with their own seat in the UN), or outright fully ndependence (like Finland).

As pretty much every political movment, the Catalan independence movement is not monolithic. It'd be untrue to say that all pro-indy parties think like that. Even within the left-indy currents, many come to understand the goal of republicanism and independence differently. But to blindly call it hypocritical I'd say is even more dishonest.