It's gaming an algorithm.
Big deals like this aren't made off one person's decision, there's all these metrics that are supposed to show the health of a company. But like anything, if you know the metrics you can just focus on that even if it's the literal worst thing to do. It pumps the metrics.
They're not trying to keep reddit alive forever, they want to juice the metrics so it's worth the absolute most on IPO day. It's all they care about.
Every argument against pineapple on pizza can be made about tomatoes.