One reason is that the Epic Games revenue split gives more to the developers. That being said though, they do enter exclusivity agreements with publishers all the time, which is anti-consumer.

But MudMan’s comment was more about how the meme denounces store-exclusive games, yet games that are available only on Steam are also store-exclusive.

GOG is a bit of an outlier. They allow developers to list their games DRM-free so their customers can truly own their games. If store exclusivity is the problem, GOG is the solution - not Steam.