Lord Krishna tells Arjuna that you need to do the work for Lokasamgraha. In 3.20, Lord says : Lokasamgrahamevartham sampashyan kartum arhasi.
A human being does work for many causes. He does it as he is living, as he needs to fulfill his desires, for purification of mind, etc. He also needs to do the work to protect the people who go in an unbecoming way.
The elders and buddhiman people in the society need to place the ideals in front of the people so that they will know how to behave in a society, how to follow the path of Truth, how to follow the path of Dharma in the life.
Normal people become victim of the circumstances as they have no control on mind. The wavering mind keeps demanding many things and the whole life goes in satisfying the mind full of sense subjects. There is need to protect such people also and that is possible only by placing ideals in front of them. Lord says, Janaka - the king was so busy in taking care of the whole kingdom still he had attained the mukti by doing the work. And the work that he undertook was the protection of people who have fallen from their Dharma. They need to be given proper support, make them understand the path of Shreyas and that needs one to remain busy.
So, according to Bhagavad Gita, Lokasamgraha is not allowing people to fall from the path of Dharma, of Duty, of Truth.