The ambassador was a veteran of the revolution. Sending him to Korea had not been a friendly act: ‘I’d got a bit critical of Fidel and the way things were being done in Cuba. I talked to many others about this and Fidel got angry. I would have preferred prison but they sent me here instead. It’s worked. Havana’s a paradise and Fidel is god. Just get me out of here. I’ll never open my mouth again.’ It was the most enjoyable evening I spent in the DPRK.Just as paradise needs its fallen angels, its Lucifer Morningstar's, so any society needs its dissidents to stay healthy. Without dissidents, and dissidence, society becomes stale and loses any belief in progress.
In the case of Cuba you get several types of dissident. There are those who wish the revolution had never happened ( but most of those, and their descendents, now live in the US), and these can be dismissed as reactionaries.
Then you get those who support the revolution but believe things are stuck and need changing (like opening the borders for travel). This dissidence can be seen as seeking to extend the revolution.
Any society is healthier for being able to satirise the leaders or call the leaders useless or corrupt or anything at all. Irreverence to leaders is healthy. After all you don't need a weatherman to know which way the wind blows.