In the third line the speaker adds himself to the pathetic crowd of the faithless and foolish what effiective does this have on the reader

The effect that this has on the reader is that it makes him relatable

Explanation:

The third line of "O Me! O Life!" by Walt Whitman says "Of myself forever reproaching myself, (for who more foolish than I, and who more faithless?) " where he adds himself in the crowd as one of the faithless and foolish, if not the biggest one, to show the reader that he has the same kind of dilemmas and human conflicts which makes him more relatable to people.

In the poem "O Me! O Life!" by Walt Whitman, he adds himself to the crowds of the "faithless and foolish", not because every single person is faithless, but that the crowds appear as if they are moving any direction. He adds himself because he is struggling with direction/purpose in life. By adding himself to the crowds, he is more relateable to the reader.