This is a very interesting topic and I'm not going to pretend that I have the answer. On some level I think we cannot be afraid of bad ideas and what's more we should learn from them. Maybe in the spirit of the dialectical method.
On the other hand, Jordan Peterson likes to repeat after Jung that "People don't have ideas, ideas have people." In his view people generate ideas to further their survival but over time ideas take a life of their own. As a result, ideas can take control over someone and spread (like religion). In this sense they have their own goal. This can make certain ideas dangerous.
It's a concept similar to Dawkins' meme that spreads through behaviour that it generates. Some memes go extinct but others can reproduce even if they are harmful to the 'host'.
As long as we are flawed we will have flawed ideas. It's dangerous to think that we can stop spreading them, because they only die when the last 'host' dies.
Anyway, it was a great post @lukestokes, it got me thinking!