The classic definition of cultural appropriation is taking something from a culture to which you don’t belong and using it for a purpose for which it is not made without understanding or respecting its cultural significance (often involving the treatment of something culturally significant as a mere accessory). The difference between this a plain old disrespect is that cultural appropriation is disrespectful, but it is not the only way to disrespect a person or their culture.
Intentions matter to the severity or blameworthiness of the act, but probably not to whether or not something counts as cultural appropriation. Similarly, the question of whether any particular instance of something (a white person wearing dreadlocks or running a Mexican restaurant) counts as cultural appropriation cannot be determined in the absence of context. So as tempting as it might be to have a singular judgment that dreadlocks on a white person are or are not cultural appropriation, the definition I gave does not allow it.
Let’s consider dreadlocks. Do they “belong” to any one culture? No, they do not. While the word originates from Rastafarianism, the hairstyle itself is nearly universal. The Egyptians wore locks, but so did the Vikings. And if we’re defining dreadlocks as just any kind of matted hair, then any human who went long enough without removing or attending to their hair would end up with them.
So then how did dreadlocks become part of the cultural appropriation conversation? In part, it comes from the perception among many black people that dreadlocks were treated as a bad thing until white people started adopting them. But it also comes from the perception that most white people who wear locks did so because of the associations with black people (associations that harmed black people, but that mostly seemed to help white people). It’s the second part that starts to look like cultural appropriation, but the underlying problem is actually one of asymmetrical respect. Sure, white people who wear dreadlocks might lose respect in the eyes of some. But they also gain a degree of social cachet that the dominant culture did not afforded to those from whom they got the idea.
Returning to the definition I gave at the beginning, it also follows that a minority culture can appropriate another minority’s culture (even if it is usually a case of a dominant culture appropriating a minority culture). It also follows that there is no conflict between recognizing cultural appropriation and fostering a multicultural society. Appropriation (by this definition) is not the only way of interacting with (or borrowing from) another person’s culture, after all, so there is no reason why one could not have a multicultural society in which everyone treated other people (and their cultures) with respect. Most people invite others to participate in their culture in various ways, and some elements of culture are by their very nature to be shared. There’s nothing wrong with appreciating and borrowing from other cultures when done respectfully. But we do have to remember that we are not the sole arbitrators of what counts as respect.