EmpressRouge and MAfan, the duke of Anjou was invited to the Prince of Asturias' marriage (and attended, because as did his father he always tried to have peace with Spanish royal family), but as a mere Excellence while, legally and merely for Spain, he is still a Royal Highness (neither his wife, nor his daughter are RH for Spain, of course they are so for France). And his future wife, while he had already announced his own marriage, was not invited.
EmpressRouge, the duke of Anjou did invite several legitimist personalities, but many, who were not invited, were deeply disappointed and some of them made it know it more or less publicly, hence the rumour that no legitimist was invited. Another disambiguation to make, is that he often repeats that he is pretender to nothing, but his refusal is to the word of pretender, because the word pretender implies that he is not, while he states he is de jure king of France, not a mere "pretender".
MAfan, king Juan Carlos acts somehow as head of the Bourbon family, as the elder crowned head which gives him some authority, nevertheless he has never pretended to the bourbon chiefhood. For instance, when in 1983 the Bourbon family resolved the case of the Two-Sicilies dynastic battle, in fact the jurists who examined legal issues were from the Spanish royal house, but the document that was edited to announce the conclusion (in favor of Don Carlos) was signed first by Don Alfonso, duke of Anjou and of Cadiz, as chief of the House of Bourbon, secondly by king Juan Carlos as head of the Spanish branch.
So, I don't think king Juan Carlos tries to usurpate any chiefhood in the House of Bourbon, simply he reproaches the duke of Anjou for his mere existence, as a grand-grandson of "behated" Franco, and most of all as the only (now with his daughter, soon with his twins) obstacle between him and the throne in ancient rules, making that he is "only" the king chosen by Franco (and approved by the elder princes and the Cortes, of course).