That is part of what posting limits are supposed to do. You get idiots that post exactly the same thing, usually rubbish, in every topic and every category. Those who do this all the time can find their posting limits sharply reduced--if they can't post more than 10 posts per 24 hour period, it makes it pretty difficult for them to put rubbish everywhere.
As for everyone else, the expanded posting limits make sense. Most of us are here to discuss and debate religion, not to put rubbish posts everywhere. Usually, it is a few idiots that abuse this that spoil it for everyone--that's why we even need posting and topic limits in the first place. And worse is when they are advertising their favorite MLM, porn site, or some crap product that no one needs and is a ripoff. Once it reaches that point (usually it's spambots doing that), it's time to go beyond the posting limits and ban such users (again, a forum needs someone watching for, and banning, spambots). I agree that putting the exact same thing in every thread, especially if it's off topic (which itself violates another rule), deserve action to limit the damage they can do.