Why do Christians stress missionary work?

because the i swear parts of the church are a cult like whattt.

Explanation:

Missionaries have the authority to preach the Christian faith (and sometimes to administer sacraments), and provide humanitarian aid. Christian doctrines (such as the "Doctrine of Love" professed by many missions) permit the provision of aid without requiring religious conversion. All is all, its like a symbol of power. why not add more missionaries to the ranks and make your church more "powerful"?

freedom of speech is also protected by the 1 amendment.

explanation:

here is pretty much what the 1st amendment says:

congress shall make no law respecting an establishment of religion, or prohibiting the free exercise thereof; or abridging the freedom of speech, or of the press; or the right of the people peaceably to assemble, and to petition the government for a redress of grievances.