If you observe the pedestrian traffic in India, not everyone walks on the left side, in fact the pedestrian traffic moves in both directions. So, there are people who walk on their right side as well.
Despite the fact that walking on the right gives a better view of the oncoming vehicular traffic, some possible reasons for why pedestrians walk on their left or right:
Need: their origin and destination is on the same side and they needn't cross the road
They need to get on a vehicle which is headed in the same direction as they are when they're walking
Psychology/ Assumption: Because the laws mandate vehicular traffic to "Keep left", pedestrians assume that it applies to them too
Convenience: Pedestrians walk on whichever side is more shaded, cleaner, clearer, safer or convenient to walk. If it happens to be on the left, then they walk on the left, else they walk on the right. Sometimes, they even walk on the centre (under a flyover or over the road divider)
I don't know how many pedestrians actually pick a side simply because of the view they get of the vehicular traffic. Actually, in the absence of proper footpaths, it's easier to walk on the left and leave the onus of precaution on the vehicles coming from behind. It's easier to blame the vehicle for negligent driving, than having to keep dodging vehicles coming from the front.