I think the idea is that you provide opportunities for it to happen naturally rather than sending people out to preach. Like cross community cultural events or avoiding things like segregation of social housing allocation.
One of the interesting things they found out after the Bradford riots was just how similar the communities in the two opposing areas were, similar deprivation, incomes, educational attainment, worries. They had almost identical complaints against the opposite community, and even the same rumours were circulating both areas about the other side having more money spent on them by the public sector an getting preferential treatment. And both sides claimed they wanted to get along with the other side but ‘They just don’t like us because we’re different from them’.
The idea is, that if there is an exchange of culture and a cultural transfer both ways, there becomes more communal commonalities which bring people together and prevent misunderstanding.
CA theory is the opposite of that because it says we do not share, we do not find things we can have in common, we do not mix our cultures together because we are separate.
Food is actually a really good example of this, because it was something that was symbolic of difference (a lot of racist language has centred around food, particularly curry) but that difference has become so small it’s lost that symbolism, which I think is part of the reason it’s not seen as CA.