Can you explain what is meant that the one who calls to misguidance bears the sin of those he misguided? Is it the exact same sin subject to the same legal penalty? Same with if he merely approved of such a sin or aided in it. What if someone guides a person to a church? Is it apostasy?

Ustadh AbdulAziz al-Haqqan

He carries the like of their sin in the Hereafter without their sin being reduced at all (Muslim), and the scholars explain that approving of a sin is itself a sin, and aiding it is forbidden. Taking someone to a church for their worship is not allowed, however it is not apostacy.