The "legitimate forces of supply and demand" seems to be the critical part there. GME stock didn't go up because /u/DeepFuckingValue bought so much of it, it we

The "legitimate forces of supply and demand" seems to be the critical part there. GME stock didn't go up because /u/DeepFuckingValue bought so much of it, it went up because everyone else did. In August 2019 GME had a market cap of $300 million so there was no way /u/DeepFuckingValue buying some hundreds of thousands worth had any real effect on its own.