I honestly don't understand the issue with "Elo Boosting"

Or to be more clear, *mmr *boosting (since "elo" is means the same thing, but is so incredibly inferior because it doesn't stand for anything).

Let's say you main a terrible champ, like Shyvana (just because a pro snowboarder eats breadsticks does not make breadsticks OP) or Rammus, and have terrible rating. But then they swap to a champ that's top tier and jump up several divisions strictly because they only use strong champs now.

Just like getting boosted, abusing god tier champions is no indication of your skill, causing you to obtain something you do not deserve. Is it simply that it's more acceptable to do the latter due to Rito's inability to properly balance every champ?