Sure, the mechanism is the same, but the scale and effectiveness are not. In your scenario, if someone wants to spread rumors about you in bad faith, they have

Sure, the mechanism is the same, but the scale and effectiveness are not. In your scenario, if someone wants to spread rumors about you in bad faith, they have to spend a lot of time and resources to make sure everybody you might interact with knows about the rumors. A service like TrueCaller makes this much easier, which I personally think is very problematic. And as others have noted, another issue is that people even might not do this in bad faith. Just as a little prank, without realizing the potential consequences.