Rank in punishments?

Uh... Can you elaborate on what you mean by rank?

No rank receives special treatment.

There is nothing about the system that effects higher or lower ranked players. However, those players may have different mentalities. So common reporting patterns may differ by rank.

If high ELO players get punished easier it would probably be because people in higher elo use their reports more responsibly. So when something happens that needs to be punished they get reported by people with higher report weights. Rather than in low ELO where people might be more likely to report things like losing lanes as intentional feeding which will take your the value of your reports.

what are you talking about? if you mean bronze 5 gets more banned than diamond then no lol. well basically yes because there are more players in bronze

Although the punishment system is greatly flawed, it however doesn't discriminate in terms of rank. The only solution is to start a petition to get Riot Games to actually make quality of life improvements to League of Legends.