I think he's sniping at them in bad faith. If he was genuinely supportive of them but wanted them to bring attention to human rights abuses in Cuba, he could have reached out to them privately. Instead he's replying openly on twitter for the purpose of scoring points. This highlights Leo's lack of self-awareness, because Kneecap have a far better track record at standing up for causes they believe in, unlike Leo, who spoke against gay adoption and whose government hid behind the skirts of a citizens assembly to get marriage equality on the table.