r/NBA has suffered from what r/gameofthrones, r/soccer, r/NFL all suffer from.

Too. Many. Subscribers.

It dilutes the content and reduces it to the lowest common denominator.

It isn't really something the mods can fix when it's a problem with this sub and pretty much every sub that hits 1 million. It's a symptom of reddit. People who are hungry for karma will subscribe exclusively to high count subreddits. They will meme their way to 100k karma, and spam and repost on hot news that they know will capture a mood ("Fuck raptors fans" for example). Over time, it then becomes a pattern across the subreddit and the culture is affected.

There is nothing mods can do about those people, because they make up probably ~40% of this sub now. The time to stop it would have been in 2015 when those people were few. But no one knows about them then because they are so few and mods can't patrol like the KGB. So it's an impossible situation and is a natural symptom of big subreddits.

Seriously, r/askreddit is probably the only non-cesspool big subreddit left when you consider what kinds of posts are frequently hitting the front page.