The opposite can easily happen as well. Hivemind makes people agree, and not necessarily because it's true but because everyone else also seems to agree. It's entirely possible to have an entire thread of people "playing along" for the joke value. It happens, and anyone on the internet has probably seen it before. I'm sure you have yourself.
I'm all for being optimistic about humanity, but this is an area I am in favour of maximum cautiousness.