We also have topics in slow mode forever, usually with a 1h posting delay.
There are some topics which some folk just get mad over, and sometimes real-world events can bring old topics back to life and re-kindle old fires. Having slow-mode ensures things don’t fully ignite before mods notice, but doesn’t stop others from making genuinely valuable comments some time later.
At times I’ve wondered if certain whole categories could benefit from all topics being in a permanent slow mode!