One might argue that the original sin of RH is marketing to people who don't have a grasp of how these systems work and not being used to having to learn these things when dealing with a consumer product.
Some of the barriers to dealing with traditional brokerages created opportunities to learn, and to put one's self into the mindset that this is a thing that is new and complex (on your first encounter), and your general approach should be researching each new thing you're trying. Heck, just the signup and annual reporting requirements on IB will make you think long and hard about each type of transaction you might want to do.
I can get behind making a business out of it, but I wonder what the long-term effects of trying to gamify and consumerify stock trading is going to have on laws, regulations, and the overall market conditions going forward. (I know what RH would say, they're "levelling the playing field for the average Joe!" But, you know, Fidelity & co. did that a long time ago - they just didn't gamify it, they gave you access to it largely as it was.)
Robinhood is, for many people, the only name they know in this space. Therefore, it must be their fault.
As the Internet grew, it raised the bar higher and higher on the "baseline" level of things one needed to reasonably know about before participating in any given conversation intelligently (bear with me). As a result, it became growingly acceptable to declare something one doesn't understand as morally "bad" for being complex, and since the experience of encountering something one didn't understand was widely shared, many folks pounced on that complexity as the problem, not their failure to grasp it.
It's infinitely easier to declare a system as "bad" than to spend time to understand why it's built the way it is. Robinhood just happens to be what many people think of as "the system", rather than the actual financial system Robinhood is built on top of.
I believe this could apply across a number of problems we're seeing online right now. Groups of people who band together (right or wrong) to rail against a system that exists for reasons they do not understand. Sometimes it's justified, sometimes it's not, but every time you get that same whiff of populist anger such as what Robinhood is experiencing right now.
Being the retail face of a complex industry apparently results in you getting blamed for the complexity.