The idea of r/wallstreetbets being a coordinated effort from the start is overblown. The subreddit is filled with general lunacy, mostly ####posts, and occasionally nuggets of solid due diligence. There's a media narrative that the subreddit is some sort of cohesive mob - as someone who's lurked there for a long time, trust me, it's not. Right now there's a collective "#### Wall Street" going on, but that is not the norm.
One poster did his own research and due diligence months ago, and put together an argument that Gamestop was legitimately undervalued. His idea was that Gamestop would stay afloat by moving to online sales model (buoyed by Chewy's CEO becoming the largest investor), cutting costs by closing physical stores, and the fact that they have a surprisingly strong real estate holding portfolio.
Nearing the end of 2020, someone else did some digging and discovered that the amount of shares shorted exceeded the number of shares available. Combining the idea of it being an undervalued investment, and the concept of potentially rising stock prices from hedge funds making irresponsible short-sale bets, people started buying Gamestop stock. It wasn't originally a massive collective effort, just once the momentum got going and hedge fund people started attacking back, people started realizing "holy ####, we're actually doing something here", and more money poured in. The more CNBC, Wall Street types denigrate r/wsb, the more people will invest. The big push this week in particular is because a significant number of options close tomorrow.
Is Gamestop way, way, way overvalued right now? Absolutely yes. But the difference between a hedge fund and r/wsb investor is that the average wsb investor has much less on the line. For the hedge fund, it's a legitimate loss. For a wsb investor, it's an investment on principle now.