People don't care about the environment when they've got more important issues like food, shelter and safety to worry about. Fuck the environment! Help the people.
My dad grew up in Bangladesh (a country of many rivers). When he was young, fish were plentiful in the waters around where he lived. Americans eat maybe a few kinds of fish, but in his culture they had dozens of different kinds as part of the cuisine (because of its abundance). As intensive farming practices took hold in the 1970's and 1980's, the fertilizer run-off got into the rivers and killed many of the fish, and destroyed the diversity of the fish stocks. When talking about the success of the agricultural methods, of course, nobody ever accounts for the loss of that important food source in the overall calculus.
The point of the story is that yes, people should care about things like food, etc, before the environment. But at the same time, environmental degradation dramatically affects your ability to secure food, shelter, and safety. E.g. it is thought that the Indus River valley civilization declined because of ecological collapse. The costs of environmental degradation on human well-being are diffuse and often indirect, which means it's easy to completely discount them, whereas a rational analysis would factor them in fully into cost-benefit analyses.
This is particularly true at a time when clean water is becoming a crucial resource world-wide. The western world can afford high-tech solutions to clean up water, but the developing world cannot. For their own well-being, people in places like India would do well to be deadly-serious about keeping their water clean to begin with.
