Without making a judgment on the truth of any particular religion, if a religion believed that I, as a non-believer, was in danger of the fires of Hell, I would find it natural for them to share their message with me. Of course, I would hope that they would do this in a considerate, non-coercive way. If people truly believe that their religion is right, and others are wrong, they have a moral obligation to try to share their religion. Not to do so would in fact be inconsiderate. Of course, all of my arguments are based on the religion itself, rather than its followers.
Conversion is a valid aspect of a religion.
It's the method that can be called into question. But the wrongs of the followers and the actual religion are two different things. An inability to separate the two is a dangerous handicap. Coerced conversions, or those made with false pretenses, if they actually do occur, are the result of wrong-headed followers rather than the religion itself, and I would be hesitant to draw any conclusions about Christianity from such acts. Likewise, I refuse to draw conclusions about Hinduism from the bands of Hindus in India who go around attacking Christian missionaries and terrorizing Christian organizations or condemn Islam because of the actions of the Taliban.