[houkoholic]

It also shows a misunderstanding and a lack of trust from both Ryuji (and in a sense the viewer's part) too.

Reflecting back, has Taiga shown this level of hostility to anyone without rational justification? The answer is an undebateble "no" - sure she is selfish etc, but she has never been this openly hostile to anyone for no good reasons, at all (acting little violent to Ryuji is not the same as the hostility she has towards her father FWIW, and we all know that Ami provokes Taiga first).

Some people would want a certain level of trust from their closest friends in that they don't have to justify to their friends every single actions in every turn, to some people that's what friendship/kindship means, unrequist trust, trust that is build upon a long period of interaction to have the faith to believe the other has a good reason to do what one does without having to spell out the reason. This is what Taiga (and Minorin as well) was expecting from Ryuji, and Ryuji has betrayed Taiga's expectation in him.