Altcoin Discussion and Bitcoin Discussion are both spam sections because most of the topics are just repetitive. After creating a unique topic, it will have another version by next week and most of it doesn't have any complexity so people will try and give common replies even they lack the knowledge required to post on that specific topic.
As we can see, most of the sig spammers are posting in Altcoin Discussion than Bitcoin Discussion and many topics on it can be answerable by a normal person. We should be more intellectual on replying to threads because we're advanced and we are here in a big community that has a lot of information. It's such a disgrace if they're here for a long time and still making dumb posts. This is also the reason why some people choose Reddit to discuss some important topics because the statements are very considerable.
If you want to discuss topics while avoiding spam, then you could consider creating a self-moderated thread. You then have the power within that thread to delete any spam comments and keep the discussion focused and relevant. You could also consider helping out by reporting spam comments elsewhere to the moderators for deletion. You could also consider posting in the "Serious Discussion" board, but be aware that, as the names suggest, any trivial topics in that board are likely to be deleted.
Agree to this, you can avoid spam replies by making it in self-moderation.
But the real cause here are the sig-spammers, they're the one who makes shitposts on the abovementioned threads.
The only solution, for now, is to report them, moderation isn't quite effective if you really want to dissolve shitposting because they will just avoid those moderated topics and post to the other threads. Remember, they're sig spammers who will post everywhere just to complete their task and earn bounty, it's really hard to stop them.