I would like to highlight Harry’s character development throughout the series. Although he made several questionable choices in GOF, OOF, and HBP, we should consider that he is a teenager throughout most of the series. Teenagers, umm, well, aren’t great decision-makers. As a teenager, I mostly acted mainly on impulse instead of rational thinking.
And talking about individuals defending themselves, not all perspectives find a receptive audience. A perfect example is in OOF, when Dumbledore testifies before the Minister of Magic about Voldemort’s return. His statements are met with scepticism and disbelief, mirroring a similar experience Harry had trying to convince others at Hogwarts.
If you want to share counter-examples, I’d be happy to hear them.