One major difference between the former Yugoslavia and Czechoslovakia, is that in the latter I am led to believe that a majority of the public wanted to stay one country. The split seems to have been a way to create more posts for national elites. Ordinary Czechs and Slovaks who I have talked to (admittedly a very small and anecdotally collected group) don't seem to have had a problem with staying part of Czechoslovakia.

In the former Yugoslavia I have no direct knowledge of anyone's opinions on the matter, but I am led to believe that a majority of several of the new countries was solidly in favor of splitting up.

I'd read the grandparent post as sarcasm, but perhaps Poe's Law strikes again.

Slovakia was allowed to leave, the Czechs and the federal government approved it. There was no recognition of the right of self-determination. That's only done with blood.