While the narrative has made him the poster boy, you can look at the past discussions regarding GME. His initial posts around a value play were widely ridiculed.
The short squeeze thesis(s) were made by other reddit users. Even those weren't particularly popular until around 1/13-1/15 when GME saw an unexpected pop. It was around then people were like "oh this squeeze thing might happen. we could test it"
The price dropped because there was no buying pressure (speculation of players shorting the stock at the top aside). Disabling the ability to buy in several brokerages removes the price discovery aspect of the system.
The short squeeze thesis(s) were made by other reddit users. Even those weren't particularly popular until around 1/13-1/15 when GME saw an unexpected pop. It was around then people were like "oh this squeeze thing might happen. we could test it"