Yes, we do each of those things because we want to strongly encourage their use. The unfairness is supposed to be outweighed by the social benefits to all by this encouragement. This is a good thing IF we think it's a good thing for people to:

- Go to parks more, and be more relaxed and healthy, benefiting everyone

- Get more education more, benefiting all of society

- Drive more.... thus creating more traffic, accidents, and pollution??

One of these things is not like the other!

At the very least, if you want to encourage people travelling (for some reason, not clear what the benefit is) you should be fair and equally subsidize car usage, transit usage, and bike/walk usage. (In much of the USA, parking is free, usage of most freeways is free, but trains and buses cost money and bike/walking is made difficult. The only conclusion to draw is that government wants to encourage usage of cars instead of non-car transport mediums, for unfathomable reasons)