Most of us wouldn't, and the rest of us will probably get on board if you rephrase oligarchy as "under the control of out of touch rich elites" because a lot of us are reflexively against anything that sounds educated.
And what do you know of it not being an impopular opinion in the US? I think you misinterpreted the assignment, it doesn't say where (locally or globally) it is impopular.
Considering almost every reply you're getting is telling you the same thing and you're the one arguing a bad position, I'm gonna have to say it's your comment that's unnecessary.
Also, no one's being grumpy to you, they're just trying to correct you. If that's what you call grumpy, maybe a thread on unpopular opinions isn't the best place for a snowflake to post.