Prince Philip is a racist, and he has made racially insensitive comments consistently for decades. Some of these include telling the president of Nigeria that he looks ready for bed when the latter was wearing traditional robes, asking native Australians if they are still throwing spears at one another, and insinuating that British exchange students living in China will eventually get "slitty-eyed." There are many more comments where these come from, and they demonstrate that Prince Philip has very problematic views about people of color.
One of Prince Philip's comments--specifically the one about throwing spears--was not actually racist. According to one of the native Australians who met him, the royal's question was based not on a misconception of indigenous culture but instead on a performance involving the throwing of boomerangs and spears that was put on by a group of Aboriginal people. Prince Philip's comment was therefore taken out of context and is not indicative of a racist attitude towards indigenous Australians.
Rejecting the premises
More on prejudiced comments that Prince Philip has made: www.mashable.com/2017/05/04/prince-philip-gaffes-list/