Yes, we all disagree with them in the sense that runs scored is a stat that is descriptive of a player's talent, which is what you are arguing. Thinking that runs is the best descriptive stat we have is beyond moronic.
Assuming those people aren't morons, they likely mean that runs is the most important stat in the sense that scoring runs and preventing runs is the most important component of winning a game. That says exactly 0 about the process of scoring those runs or the talent of the player scoring the runs.
Like others here, I refuse to believe you're this stupid. Let's say two players both score 100 runs in a season. The first player got all 75 runs through a plethora of extra base hits, walks, and stolen bases. The other scored half of his runs by getting hit by pitches, reaching on errors, and lucky singles, but he just happened to hit in front of two monsters who hit a ton of home runs. By your logic, those two players are essentially of equal talent and value because "runs is the most important stat in baseball and a bunch of all time greats said so"