I think I get where he is coming from, being the proud owner of multi heritage hair myself 
It is racial stereotyping but on a milder scale. It is associating R&B (rythm & blues) music, a product of African/ Carribean culture, with afro hair.
The owner of Reggae Reggae sauce does it too and that makes him clever at marketing but I do wonder if his background gives him more right, as it were, to utilise such marketing. I think it can be seen differently when it is done by a big corporation that has no links to African/ Carribean culture to begin with.
I am not Asian but I find that new ad about creating an Asian masterpiece (cannot remember who makes it) in minutes reduces the image of some of the worlds most amazing artwork to something we relate to as a novelty, it devalues its legitimacy as serious art. I think the tag line is something like "An Asian masterpiece can take years, or minutes", cutting from a girl seriously working on a piece of art to someone making a jarred sauce of sweet and sour sauce. Its like this other culture can be bottled and treated as a marketing gimmick, or novelty.
Thats might be how your DP is taking it. I wouldn't buy R&B for the same reasons, the association between thick curly hair and a cultural art of expression would put me off. I am not uptight about it, if someone bought it for me I would think it a not thought through gift but wouldn't throw it out. But I do understand your DP's feelings, its like trying to bottle his culture up into a gimmick and racial stereotype, rythm and blues = affro hair.
Every culture experiences it, take Yorkshire tea for example. But Afro hair is associated with negative ideas and the product description even talks about controlling frizz:www.lushusa.com/shop/products/hair/hair-treatments/randb so the idea is that this frizzy hair that is being associated with African/ Carribbean culture needs controlling.
There are lots of feelings behind this and I know my African/ Carribean freinds would not like this either, but some people wont mind.
If you are looking for something for your daughters hair, have you tried Dark N Lovely? It is available at all African/ Carribean hair shops, there are also lots of other childrens brands made by African/ Carribean people for childrens hair specifically. Maybe use cocoa/ shea butter or carrot oil which is amazing!