Victoria Stillwell herself admits she has said and done a lot of things about dog behaviour that she would no longer stand by. Mainly due to her only really getting the show because of her background in acting. She had no professional qualifications in canine behaviour - but tbf has worked hard in later years to try and make up for that and to correct some of her earlier advice which was wrong/dangerous.
Yes, there are lots of things that owners can do to help sometimes and I actually don't think there are any bad dogs, either. But that's not the same as thinking that difficult dogs are the owner's fault or that everyone with a difficult dog should feel guilty or think they have failed the dog somehow.
Aggression and resource guarding, are two such examples.
Both are multifactorial and have links with the dog's experiences before an owner ever gets near them. Whilst SOME dogs with those behaviour traits can be helped, the best that many owners can hope for is to be able to safely manage the dog and their behaviour. For some owners, these behaviour traits are more than they can cope with. A lifetime of managing potentially dangerous behaviours with the risk of getting it wrong once and the consequences that brings is too challenging for them. Understandably.
It is unfair to those owners to lump it all into a "there are only bad owners" bucket when problem behaviours in dogs (as in everyone) are often causes by many factors, each coming together to be expressed in a challenging way.
I wish more people understood more about dog behaviour (as someone with qualifications in it, this speaks directly to my own path) but I hate the over simplification of the "there are only bad owners" phrase.
I should also, arguably, learn to get off my soap box 