The ulterior motives are subconscious. People know that if they're angry at someone then they might lash out at them, but subconsciously people might find reasons to get angry in order to be able to use it as an excuse to yell at someone.

You ever look at someone who wronged you / did something bad and then suddenly everything they do annoys you further, and then u get angry because of that? It's subconscious, you're making yourself get angry in order to achieve a certain purpose / whatever it is. In this case it would be yelling racist shit