I'm sure many others purchased it for the Steam keys that were advertised on the bundle page. Seems like a bait and switch.
Which bundle page? The dialogue that comes, if you actually click the button to get the bundle?
This is what it says for me
Buy 1439 games
Download this bundle by purchasing it for $10.00 USD or more.
Add $5Add $20
Note: Steam keys are not included with bundle purchases
I guess they forgot to add that note from the beginning. It also appears on the games that happen to have a Steam key for regular purchases.
But while we are at it, those are not 1439 games. It's 1439 items. Itch is really unprecise in their wording at some places. There is some tools and music in that bundle. But mostly physical games. Only 161 of those items are video games that can run on Windows. 161 is still a huge number and there's even a page that exist for digging through those Itch mega bundles.