They don't charge you money to encourage carpooling and more environmentally friendly transport. They charge you money because they can.
If they were really environmentally concerned, they would be pumping the money they collect into a fund, with all the other local companies, to be used to improve local infrastructure & transport links.
Instead it becomes pure profit for something they would be providing anyway.
I speak as someone who lives too far to bike, not on a reasonable public transport route (two buses and a train) and in a different direction to most other employees at my company.
Throw in the random late hours and its impossible to share with anyone.
They make us pay for parking where I work. It's between $90-135/month. They want to encourage people to car pool, van pool, use public transport, bike, etc. It wouldn't be so bad if priority for the cheap spots went to the poorest paid, but usually it's by classification. The highest-paid faculty end up taking all the cheap spots, and the secretary that's been there a year has to pay the most. At least they price the spots according to their desirability: the temp controlled underground parking at my building is the most expensive, and the open air lots 2 miles away are the cheapest.