Let me see if I've understood you correctly:
To me, you seem to be saying that people who call themselves Christian but believe liberal or humanist "theology" will be punished more severely in hell, because they are part of "the church". But surely, if they are truly part of Christ's church, that is, if they really know that they need a Saviour, and have come to know that Saviour, the Lord Jesus Christ personally, they won't be going to hell at all.
Perhaps you meant that the liberal/humanist organisation they belong to calls itself a church. But then, that doesn't fit your argument, because the Mormons also call themselves a church. ("Church of Jesus Christ of Latter Day Saints").
I'm assuming in all this that you are using the word "liberal" theologically, not politically.