I find it difficult to comprehend what all the fuss is about!
Each cartridge has been designed for some specific application although some enjoy wider application and usefulness as compared to others.
To use an automotive analogy, how would you view somebody who complains that a 10 ton truck doesn't handle like a sports car and does a standing quarter measured in minutes instead of seconds? Or vice-versa?
On the other hand I would have thought that "Dad's Army" type shooters would have embraced the 300 Blackout for their putative competitions, as the ranges they shoot over are rather modest and the 300Blk chambering if exploited intelligently has the capacity to offer many advantages for their style of shooting.