All I can say on this topic is we are blessed that this is not a salvation issue, as long as we have faith by grace and understand the gospel, accepting Jesus Christ's sacrifice and having Him as our Lord and Saviour that is the most important thing. God is not a respecter of persons so for Christians who do partake in pagan holidays unknowingly or even knowingly, they shall be judged as we all will be but if they are saved then thank God for that.