The word Dharamsaal literally means the home of dharma, or a temple. Just like paathsaal means house of education or school. Guru Amardas says, "Your beautified the earth like a temple" in the following line:
Where the Saints and the Holy gather together, there they meditate on you.
Places of worship are made so saints can get together, meditate upon the one and sing the ONE's praises. The purpose of life is to sing and the earth has been designed to be a place where this singing can be done. The earth has been designed by God to come together and sing. Earth becomes beautiful when we come together and sing. Such a beautiful concept.
What is singing other than just following the command of the ONE. Gurbani says Sabhai Ghat Raam Bolai or Every heart is singing in the temple of the earth.