>”Why would someone let an elected official enrich themselves and their friends with your money? Why would the legislative branch allow that?”

Let is a heavily loaded term here. The most an individual can reasonably do is cast their single vote in an election year. I could attempt to bring a lawsuit against a politician, but it would almost certainly be thrown out due to a lack of standing. Activism is certainly an option, but that is really just an effort to convince others to cast their single vote differently. Outside of those options, one would have to break some laws.