Randomly getting my TD Ameritrade account shut down without explanation (they specifically state that they wont give you a reason and tell you to not ask), and all my positions closed (for a loss) a week after moving to them was a pretty good reason to move to Robinhood. I hadn't even applied for margin.

Robinhood seems to people, however ignorant the impression may be, that they don't act like the Big Evil Wall Street Corp guys. So it's not unreasonable to use a good platform for analysis and use Robinhood to trade.