Did I interpret that wrong?
I can't speak for Ghostcrawler, but my interpretation is a bit different. Boards and Forums are best used as qualitative data; this gives them direction on how to change the game. Boards and Forums don't work well as quantitative data, since most players don't use Boards or Forums (a popular thread on Boards can usually get between 40-100 upvotes, maybe more, and a few hundred or thousand views. A popular Riot Announcement post can usually get 100+ upvotes and have several hundred thousand views; and this is just for the users that regularly check the site. The playerbase overall is ~70 million).
On the one side, you can look at data. Say Champion Y has a 55% win ratio and 1% pick/ban ratio across all elos. What could this mean? A lot of people might look at the stats and say that this champion is overpowered, due to the higher than average win ratio. On the other hand, the champion has a very low pick/ban ratio, suggesting that there is a relatively few number of players playing that champion; this could mean that those few players have greater expertise with this champion and thus are likely to win more of their games. This seems okay. However, you look at Champion Z, who has a win ratio of 55% and has a 70% pick/ban ratio, and something seems strange. It seems strange that 70% of the player base could be an expert in this champion, which seems to suggest the champion itself is too strong.
This is about the limit of what data can give you. Perhaps you can identify a problem champion, that is overwhelming all areas of play in all regions, and as a result, should be toned down. How do you approach this? This is where player feedback comes in, and, as is the purpose of this thread, good feedback becomes very important. If you have a thread that says "omg rito Champion Z is so op nerf plz", it doesn't tell you much. You understand there's a problem, mostly because the data also supports it, but there's nothing for you to gain from this thread, aside from a (relatively small, due to the smaller userbase of Boards) portion of the community is having trouble vs Champion Z. However, if you have a thread like "I think Champion Z is too powerful because their Q provides high early game damage without much counter play for the following reasons..." etc. there is much more to be gained; you now realize that it is Champion Z's Q that is problematic, and that it is the early game damage without counterplay that is the problem. You can now examine this closer, make changes on PBE, and see how the changes affect the PBE environment, and if that feedback was correct. If not, search for more feedback on the direction to take the champion.
Another case is where you hear a complaint like "I think Champion X is too strong because their E gives them a reliable gap closer and escape". This could be a problem, but you look at Champion X's stats and they have a 45% win rate and 10% pick/ban ratio. Again, it might be a problem, but the low win ratio suggests that most players are having an okay time dealing with Champion X, and that this player making the complaint might just be having a hard time dealing with this champion. You keep an eye on this champion because the complaint raised a valid point, but the numbers don't support this champion being a problem case at the moment, so you hold back on making changes at the current time.
This is the general structure of how the feedback works in an ideal sense, albeit greatly simplified. They need both systems of data/feedback in order to make complete decisions. They can't act on feedback alone, since feedback typically represents a small portion of the overall community. There may be a majority of the playerbase that will agree with the feedback, but the numbers (upvotes and view count on the thread) don't represent that larger playerbase (since they don't use Boards), and so Riot can't assume that the feedback represents the opinion of the majority.