Genuine people from all around the world are welcome to India. Many Africans are students in India, so they definitely do want to return to Africa after their studies to improve Africa etc...being doctors, engineers etc.
Unfortunately some are bad apples and bad apples (drug dealers, pimps etc) spoil it for everyone....and there are bad apples on other side too that do the generalisation. We are seeing it a lot in the US now w.r.t latin americans/mexicans esp the illegals.....so I am not surprised its also happening to some level in India.
But I am sure we will see continued flow of migrants between India and Africa over time (lets not forget many Indians also go to Africa to set up business/contract farming/trading even studying too etc)....just like there is still many Indians going to Australia even after those spate of racist attacks on them that happened those years back. Most people fundamentally realise that most people are not vicious hooligans, but the vicious hooligans (alongside the genuine criminal elements that spur the generalisations) dominate the headlines when incidents happen. Its simple how media and human emotions work.
Thats not how majority mobs work. You think the Idi Amin thugs took Indians in Uganda on ....in gentlemanlike one on one fashion?