Well, most of it really. The problem is that the writer wrote in absolute statements.

[hider=Text Dump]Maids can be violent without their friends being hurt (Aradia beat Vriska for revenge towards a personal slight, and Equius because he took advantage of her trust), and they aren't selfless (Aradia spends almost no time tending to others). Princes do not explicitly hate being wrong (Dirk is upfront about his mistakes, and while Eridan wasn't and tended to forget about them, he admits to most of the mistakes he was accused of) and do not inherently hate their aspect (Dirk is extremely strong-willed and manifests multiple selves which, although he conflicts with, eventually comes to terms with. Eridan went on a murder spree because he thought there was no hope left and because he felt everyone had turned against him, not because he disliked everyone else's efforts). Seers are not idealistic, and do not necessarily distance themselves from others (Terezi is cynical and highly involved with others). They do not always value their aspect (Rose has no particular affiliation or opinion regarding fortune, even after god tiering, until long after the fact and living with it for three years). Slyphs are not lonely by choice (Kanaya initiated the exchange between herself and Rose, directly saying she wished they could be friends, and tried to get Vriska's attention for years). Pages are not not optimistic or idealistic (Horuss was projecting a facade because of his new relationship with Meulin, and is shown to dislike being so mindnumbingly positive all the time), they don't necessarily always work well with others (Jake. Just Jake), and they don't generally share their aspect with others (Horuss turned his aspect in on himself without extending its effects to others). Knights are not necessarily strong mentally (Dave is the most susceptible to exile commands out of all the alpha kids and is often confused or expresses dismay over complicated mechanics), and Time is not associated with money (with only Dave ever exploiting the aspect for that purpose). There is no known of roll fulfillment for the Blood aspect's god tier (and ectobiology is not associated with the Blood aspect).

The rest of the information in the classes section and basically all of the aspects section cannot be either validated or disproven because, again, almost nothing is known about them.[/hider]

Really, it seems like the writer took the most prominent displays of behavior between characters of certain classes and generalized those behaviors as universal across all instances. They don't leave any wiggle room, and so there's contradictions. Class and aspect do not define the character, they are /assigned/ to the character based on fit.