I don't think Pat has ever said Anglo-Saxon culture has been a superior one, but has simply noted that multiculturalism and unity have often been at ends with each other. Sometimes it's not a big deal, but you look at countries with a clash of cultures and it can really hold them back. Examples are Muslim/Christian nations, Muslim/Jewish nations, the Baltic states with various languages etc.
I do believe that assimilation is important, but not at all to uphold a white/christian society as frankly I'm not even a Christian. And although I don't see color, people tell me I'm white and I believe them because I love hockey. But I do believe a common culture is important to a strong nation. I think a nation can change for a greater good because of legal immigration and assimilation, but what is happening now is a shock to a system and a far cry from natural assimilation.