Okay, I haven't read 'His Dark Materials'.
So how do I know it isn't anti-Christian?
Because its premise is that God is evil.
Christianity has dealt with that premise extensively.
Just look in the Bible under 'false Gods'. The Bible tells all about false Gods!
And the Bible agrees with Pullman! The Bible agrees that we should be against false Gods and their false Church, regardless if we believe there is a real God.
So go ahead, read it. Learn just what we should do with false Gods!