After reading various history pieces on Havel, I think that it's very likely that he changed his mindset a lot between 1964 and his effort with "nonpolitical politics."
But at the same time, I know that even though Communism is partially stopped in government practice for a short time, making difficult changes to a culture in a large population is another matter. It's easy for a people to try something new with extremely idealistic expectations only to revert when things don't work out the way they'd hoped or as quickly as they'd wished.
Especially when 25 TO 50% of the population were working for the Communists in one capacity or another. As I mentioned above, I think the hardcore, committed Communists represent a far smaller number, probably 5-10%...and the number of elite Communists a smaller number still...but talk about a fifth column!!!! The upper echelons need to be purged and brought to justice, otherwise we are importing that very same fith column right into our own ranks (re: EU, NATO, etc).