That's an old support page from back when Apple originally dropped support for 32-bit apps, it wasn't written with the discontinuation of the ~~32-bit~~ Mojave Steam Client in mind because at that point they were still supporting it. They won't be removing 32-bit games from your libraries, but the ~~32-bit~~ Mojave Steam client will eventually stop working, and without any warning, when a future update inevitably breaks compatibility. They may still be in your library, but you wont have any way to install those 32-bit games anymore.

This article isn't stoking fear imo, it's very straightforward about what's happening here. At some indeterminate point in the future, there will be no more installing 32-bit MacOS games from Steam and anything you already have installed will presumably need to be run in offline mode because the client will stop working.