Reddit is filled with very vocal terminally online people. Their views and actions are not representative of normal human beings.

Reddit is at the core forum platform, therefore it's as misleading to attribute whatever is happening at any one [group of] subreddit to the whole of Reddit as it is misleading to do the same with closed Facebook groups.

Remember forums of old. Larger sites with daily visitors in the thousands already had nearly isolated topic silos within the forum. The effect is even stronger here.

Facebook alone is far more mainstream than Reddit, I would say. Thousands of times more.

You've identified the problem. It's never "reddit", it's a specific subreddit. It really depends on the size of the subreddit. Smaller subreddits can easily get riled up, and also create a sealed echo chamber by banning people left and right. But I wouldn't worry about a sub unless it was really big.

For example: I'd say HBO should worry about what the game of thrones related subs are saying about their latest show (which is good, shoutout) but only as a vibe check. The normies will always outnumber the kind of people who go to a subreddit to discuss their favourite show. Normal people just watch and forget.

My guess is that it is more: the people that are concerned are posting about it. And those that aren't, aren't.

So you are just seeing a biased subset of the (relatively) mainstream reddit.

It might be that the demographics of Reddit skew toward low economic relevance but high unique views.