You make a good point , and I should have chosen my words with more care. It is never helpful to lump a group together for the purpose of painting them all with a brush that does not fit them all.
As the video shows, yes it is helpful to say “would everyone that has been bullied” step forward… or those who are step parents, or lonely, etc. That is grouping people with shared traits.
In a strange way, we sort of agree here. Because when someone says “millennials are all entitled” or “boomers ruined the environment” etc., we do them all an injustice. Perhaps some millennials are entitled, perhaps some boomers didn’t care about the environment, but there are many who don’t fit the stereotype and to lump them all together is not correct and I do believe it makes a writer less credible to do so.