Obsession about equality as a central tenet in Christianity? You may want to read up on the crusades, slavery, the 30 year war, how even other Christian immigrants (Irish, Italian, etc) were welcomed into the US etc.
Also, just because some Christians share some of the morals of your humanist friend does not imply any relation whatsoever. There appears to be that desire from religious groups to often exaggerate and emphasize any such correlation as something more. When your friend meets with his family at the end of December and again at the equinox in spring - do you point out how Paganist he is? And, when you as a Christian presumably celebrate Christmas and Easter with your family - do you tell them they are just like Pagans as well? If not - why not?
Also, just because some Christians share some of the morals of your humanist friend does not imply any relation whatsoever. There appears to be that desire from religious groups to often exaggerate and emphasize any such correlation as something more. When your friend meets with his family at the end of December and again at the equinox in spring - do you point out how Paganist he is? And, when you as a Christian presumably celebrate Christmas and Easter with your family - do you tell them they are just like Pagans as well? If not - why not?