Because without other people challenging your opinion, you can't possibly take into account other people's experiences and therefore will have far less informed opinions. It is not an ego complex to challenge publicly stated ideas or opinions. It might be depending on HOW you challenge that idea/opinion, but that's a different conversation. I'd argue it's pretty dumb to publicly state an idea or opinion, especially on a place like video game feedback forum and think it can't or won't be challenged.