Honestly its rude to be invited by a country to meet their president who decided to respond to your criticisms of their administration only to not show up and go meet the opposition.
Being invided and then no showing shows complete disregard to basic diplomatic Etiquette since it was a mission to show solidarity against the embargo
Bonus socdems being cringe part 4.5: about another member that didnt show up to the presidential meeting
Show
Deeply unserious people
Other groups send delegations to Cuba regularly, including PSL and Cuba-specific groups like those opposing the embargo. I'm not sure if FRSO has a delegation or not, or whether they join some of the amalgamation delegations that go every do often (they probably do one of those options).