Robinhood's statement was not great but I think people are underestimating the possibility that the technology (not just Robinhood but the entire system that underpins the market) simply cannot handle this much interest and volatility in a small stock. https://twitter.com/AOC/status/1354830697459032066

56% of Robinhood users own GameStop stock. How can they guarantee that trades are being executed at the stated prices? How many were bought on margin aka Robinhood loaning them the money and thus risking their own solvency?

This is admittedly above my pay grade. I don't know enough about the backend of this stuff but these issues seem more likely than some super nefarious plan that people are speculating about on here.

T+2 is a already a pretty recent change. The settlement period used to be longer. https://twitter.com/zGuz/status/1354854476801302528

This is a good thread to read for more information. https://twitter.com/KralcTrebor/status/1354952711217807364