Seems to me....
It seems to me that:
-The pitts pilot was within his rights to take off.
-He should have made a radio call
-Regardless of whether glush was flying a piper or an aircraft with higher performance than the pitts he was wasting time by backtracking 20m when over 250m is available, especially when he is so concerned about runway behind him.
-The pitts pilot probably assumed that when glush started backtracking he would backtrack for long enough for him to take off safely.
-Finally, both pilots were not on top form that day.
Investigation complete
However, I do understand why glush was annoyed