I wouldn't call it corrupt. It's just as "corrupt" to insist that teams that "earn" more due to higher attendance and better TV revenue give it away to other teams. In that scenario there would be no incentive for teams to try to do better economically...what difference would it make for me (as a team) to improve my fan experience in person or on TV so that attendance or ratings go up? If I earn more revenue I just have to give 95% of it away to my "competitors".
MLB is in a tough position balancing economics with on-field competition. They are trying to find the right balance so that the lower earning teams aren't at an impossible disadvantage with respect to the big-market teams. We can argue about where that balance is, and whether St. Louis deserves revenue sharing, etc. But they HAVE made it possible for teams like KC, Miami, and Baltimore to be competitive if they are run well (at least in the short term) and StL has been more than competitive in the long term. Many of us believe they could (or should) do more for the small market teams, or that they need to better define "small market", but many fans don't share that belief. Some of us are not too upset that we're in the running to sign Manny Machado, for example, and BALT and Miami aren't. But we are upset that the NYY and LAD have an edge on us, I guess!
It's only fundamentally corrupt if you believe that each team deserves precisely even revenue. But I wouldn't call disagreeing with that belief corrupt. It's just a matter of philosophical disagreement, and I hesitate to label those who disagree with me corrupt.