Even in the event that salesmen, politicians, corporations, etc, are genuinely and naively ignorant of something that causes an issue, their station is such that they should still be held fully at fault. A layperson just going about life the best they can is expected to fail, and make mistakes. But someone elevated to a position of power, or who’s entire schtick is attempting to gain from others, should be held to a much higher standard. Naturally, there are laypeople who can be malicious and feign ignorance, such as there are corporations that can have previously undetected safety issues that end up causing an accident. In the latter case, though, it makes far more sense to assume malicious intent until the company can prove they’re not negligent. Humans are social creatures who need to extent trust and form bonds with others, but extending that trust to people who are incapable for caring about you personally is a massive mistake.