Underperformance over short to medium to even medium-long periods might mean one of two things: the stuff in their wheelhouse is very cheap right now, or they are terrible managers.
Not really. All it is telling you that through various cycles over a fairly long time, a passive index was more efficient manager of your wealth than this manager. 20 years is a significant chunk of time.
I undertstand that the manager could be particularly unlucky when the point at which the end date for comparison is set is particularly unfair or untypical.
In this particular case there is plenty of data available that suggests that this is not likely to be the case.

Given the data I saw for this manager, I wouldn't waste time going through the convolutions to find some justications when it comes to choosing a wealth manager for myself if there was ever a need. Obviously others might be more generous with their money or their time !