The Bible does not encourage us to enforce a Christian lifestyle on others but actually discourages it:
Revelation 22:
Seal not the sayings of the prophecy of this book: for the time is at hand.
He that is unjust, let him be unjust still: and he which is filthy, let him be filthy still: and he that is righteous, let him be righteous still: and he that is holy, let him be holy still.
Matthew 13:
The kingdom of heaven is likened unto a man which sowed good seed in his field:
But while men slept, his enemy came and sowed tares among the wheat, and went his way...
...The servants said unto him, Wilt thou then that we go and gather them up?
But he said, Nay; lest while ye gather up the tares, ye root up also the wheat with them.
Let both grow together until the harvest: and in the time of harvest I will say to the reapers, Gather ye together first the tares, and bind them in bundles to burn them: but gather the wheat into my barn.
We should look at sinners with compassion as we would want to be treated ourselves because we are all sinners. We should not openly support them in their error. But that's another subject.