> Most people want to be helpful to others. This works fine when it is with a limited no of in real life interactions with mostly reasonable people.

I don't think it has anything to do with the internet (whose scale pose many problems but not this one): anyone that founded a product/start up can tell you that people will give you “advices” and “suggestions” all the time when you talk about your project, and “don't listen to random suggestions from people you've just met” is one of the first advice you're being given when you're talking to other founders.

It doesn't even need to scale above a handful of people to be a nuisance that harm your project if you listen to them.