I've noticed the Only Ones saying ADC's aren't Too strong are Plat or Lower ADC mains
With a mixture of supports thrown in. Considering this is 30-40% of the playerbase, it's not surprise Riot has brought ADC as a role so extremely far into the Broken zone, but this also highlights a major problem with gameplay balance boards when it comes to League of Legends.
The only board I've ever been to that values a higher elo players opinion more than someone who is silver or gold is Reddit's summoner school. On that site, they have flairs designated to the right side of your name stating your elo, which helps filter some of the lower elo bullshit from the actual reality that is League of Legends. They also try to avoid throwing rants around in place of actual gameplay discussion. For example, if some silver 4 player starts ranting about how Yi has no counter play, the post would be deleted for not following the sub reddits rules. If, however, a silver 4 player asked "how do I beat yi," or a Diamond League player made a post saying, "how to beat yi at lower elos," it would stay up.
This is why "circle jerks" (I hate that term, because it's only used on a post you disagree with) get so massively upvoted saying blatantly untrue things. On these boards, a Silver players upvote and Thread has the same visibility and power as someone who is Challenger. There is no way to discern who's who without copying and pasting their name into a third party source, which most people don't have the time for.
And for everyone's inevitable, "Bronze opinions matter to!" I will tell you first hand, I understood so much less about this game when I was gold and below. There's a threshold in this game, right around high plat that changes it drastically. All the sudden the meta game starts to effect you. There are no more Yasuo, Darius, or Yi bans. It's all going to revolve around who the strongest objectively is, and those that you play against are playing what is good and nothing else, unless they are some one trick. Your gameplay knowledge increases and you begin to look at the game from a more logical point, and everyone who hasn't BEEN up here will never understand it.