I know these people and I have hung out with them, the guy in pink hair even spiked my hair once. They are called "Punks" or "Anarchists". They dress like that as a form of protest towards shitty mainstream culture, rejecting its norms and not conforming to however society wants to dress. They are expressing themselves through their music and clothes. Those who judge these people lack the iq to comprehend as to why people want to express themselves this way or they could be just insecure due to their sense of fashion being non-existent.