Rank Elitism isn't a boards issue, it's an in game issue
People talk about people using rank to discredit arguments or justify ignoring feedback on the boards.
However, i think that this is not really where most of it occurs. It's far more common to see people complaining about your in game decisions, based on their prospective, then ignoring your perfectly sound explanation as to why you did what you did, and how doing what they wanted you to do would've resulted in a worse result.
The problem isn't that the person posting on the boards is using rank as an argument. The problem is that by giving someone a rank, which can't be assumed to accurately gauge skill of players in normal games, is viewed by the average player as a credible representation of a player.
I think it would be beneficial to only make the borders appear on the in game prostrates in their respective ranked game modes, or at the very least not in blind pick.
E.g.
In my recent game (blind pick), me and my morg support got caught in between 4 enemies due to a ryze ult. But somehow I apparently had worse map awareness **because ** "i'm silver".

when they collapsed on us, they initially focused morg. Then she actived her zonays, so I took the opportunity to escape, because they had collapsed onto her, and circle around for the counter engage from my team who were still probably 4-5 seconds out. Keeping myself alive, which resulted in 2 extra kills and one less death.
She then goes on a tirade, about how i have no map awareness and that it's evidenced by the fact that i'm silver, and therefore bad.
let's ignore the fact my season 6 rank was based on a sum total of 61 flex queue games with friends 1/4 of which were on morde... in season 6... [zombie-brand-facepalm]