Agreed. That's the point. Mingus deliberately recorded more music than he would use.
Why not listen to false starts, mistakes, and between-song-banter too? That's the difference between listening to a session and a finished album.
I tend to agree with this. The Mingus Dynasty edits worked for me too. I had a similar disappointment when listening to Monk Live at the It Club on cd - the power of the performances seemed diluted. Sadly, economic circumstances led me to dumping my lps before the new cds arrived. After the fact editing is usually done for a reason. That said, it is interesting to have the "complete" performances for archival purposes.