[pizza]

P(malice) <= P(competence & intent); P(stupidity) >> P(competence & intent)

That said, Hanlon's razor can't explain away evidence.

[unclebucknasty]

   if (benefit > 0) {
      P(malice) >> P(stupidity)
   }

[newjersey]

Yup, when I make a mistake in my income tax filing and over pay by $2k that's incompetence. I wouldn't be so sure about attributing an unreported offshore shell company holding millions of dollars as incompetence.