Your perception of people repeating this line is very weird to me.
Hanlon's razor is not something you "invoke" to end a discussion. It is not a constitunional law. It is not a physical law. It is not even an informal guideline to guide arguments in the internet.
It is just a clever line you quote to represent your opinion. It is just like to say "occams razor", or "red herring", or any other expression that means something.
I think you take internet debate too serious and give way, but waaaaay too much importance to the words some random person chose to express their opinion.
I read the original sentence with exact same meaning of "i think it was incompetence, not theft".
Why to use this expression then? Because maybe they thought it was a shorter way to express the whole opinion.
The difference is when you call something a "red herring" you also point out why. Or if you invoke "occam's razor" you simultaneously propose a simpler explanation. Whereas Hanlon's razor comments like the one above literally do nothing except say "Hanlon."
Anyway, I don't think me and GP are alone in being irrationally annoyed by this cliche.
I think your accusations at the end are unfair and out of place, not to say ridiculous.