First, the Catalan & Basque separatists were referring to Montenegro, not Kosovo.
Second, the Kosovars are saying almost the same thing: "Why is it OK for Montengego to vote to secede, but not us?" Both Kosovo and Montengro were incorporated into the entity most recently known as Serbia & Montenegro by force of arms ratified by Great Power fiat at the end of WWI. Both fought revolts for years that were brutally suppressed. However, Kosovo voted for independence in 1991 and then suffered through the Serb pogroms against the Albanians culminating in the ethnic cleansing campaigns of 1998-99. From their viewpoint, even more so than Montenegro, they deserve independence yesterday.