Political oversight is the issue: to supply revenue, a politician is given a choice, between raising taxes and issuing more fines. Raising taxes is always a difficult battle, while jaywalkers or people who speed on the highway make a convenient target. So the latter happens more than it should.
These tickets disproportionately target the poor, who have the hardest time paying them on short notice, leading to additional fines that accumulate and build on each other. So officials are incentivized to either game the system by doling out tickets more than is socially productive or by targeting people who are most likely to pay back the most in fines.
The revenue has to go somewhere, but it absolutely should not go into the pockets of the agency issuing the fines. Where should it go? Best case would be to reimburse the people harmed by the social ill that's being fined: that level of targeting is hard, leaning toward impossible. Next best is to give everyone an equal share of the fines: this is also difficult, and overly costly for what would amount to a couple bucks. Third best would be to have it go into the government's general fund, to the exclusion of the agency issuing the fines. Fourth best would be going straight to the general fund.
Second worst is giving it to the agency issuing the tickets, which is where we're at now. Worst of all would be allowing the officers issuing the fine to pocket it themselves, which leads to the lowest levels of ability to audit and the most perverse and misaligned incentives.