It's impossible to apply effective collective guilt and to properly human-bash, if the "we" isn't used, that's why it is so frequently invoked that way. They know that the extreme majority of people had nothing to do with it when they use that phrasing, it doesn't have any captivation what-so-ever if you say: an extraordinarily small number of people out of seven billion are/were the problem/cause. It applies similarly to nearly every popular topic of human bashing, from animal cruelty to war (just as when people say their faith in humanity has been restored because of the act of one person, they're making a similar intentional error of collective application).