Obviously I have no evidence to back this up, but it seems to mostly be used on the Internet in an intellectually lazy way to avoid confronting the fact that many people really are malicious, and the effect of Hanlon's razor, in my experience, is to lower the quality of discourse (which is why I think its invocation is usually malicious even if it's not intended to be).

Edit (addendum):

> but then I remember to never ascribe to malice that which is adequately explained by stupidity.

Even though there's plenty of evidence of malice in Hollywood. For an example that everyone agrees on, there's military propaganda in almost all movies and video games made about the military.