This Hadith does exist, but extremist Muslims have interpreted it incorrectly. There are several examples of such an incorrect interpretation. Literally, the term ghazwa refers to safar or peaceful travel. According to a Hadith:

“A group of my ummah shall go for a campaign in Hind and it has been saved from Hell.” (Sunan an-Nasa’i, Hadith No. 3175)

This safar or ‘campaign’ can be of anything. It could even be of education or social welfare or to spread the peaceful message of Islam.

Source: The Seeker’s Guide