why is it sideways anger?

[prplchknz]

why not just be direct and call it misdirected anger? I mean it doesn't come out of one's side. It's just misdirected. that's like when people mis use the phrase throw under the bus. which means to destroy one's reputation. when you say "so and so got thrown under the bus because he ate a tic tac" is not the same as saying "so and so got thrown under the bus because he ate his wife"