Most of the collective nouns in the list you found are real, but many of them are used very infrequently. Some are invented - inventing appropriate collective nouns is a fun game for English speakers who like playing with words - for example one might have a dissonance of thereminists, or an interference of theremins.
One of the collective nouns in your list (a flange of baboons) was invented for a TV sketch show (http://youtu.be/beCYGm1vMJ0) but has subsequently been used in serious scientific research papers, and has consequently been accepted by the Oxford English Dictionary (the de facto standard for English) as a part of the English language.