Reddit Inc. itself lost really hard.

For Reddit Inc., the winning conditions are to get share prices up to the roof, so when the IPO happens the current shareholders leave with their pockets full of money. However, everything that is happening shows:

That Reddit does not have multiple stable sources of income. The only main source of income will still be advertisement money.
That advertisement money will run dry, as users are leaving the platform or outright boycotting it.

Both increase the risk and decrease the expected profit. Nobody is insane to invest in a company like this.

For the community it depends on your goals.

I count the situation as a big win; alternatives became more viable, Reddit as a platform will become less and less relevant, and the scummy company will lose lots of money.

If however you expected Reddit to play nice with its userbase (e.g. reverting API price changes), then count it as a loss.