Your comment sounds similar to the explanation from the mouth of Interactive Brokers chairman and founder Thomas Peterffy [1]. His comments are based on a broader concern beyond just Robinhood.
I think a lot of people don't understand what I can only describe as the physics of the system. Like a utility, there is only so many electrons that can get pumped through the system from generators through the transmission system, through substation and distribution networks to your house. It is big and powerful, but if there is an unplanned for event that draws too much power it doesn't matter how much generation you have, the system just can't take it. Substation will pop, power will go out if not isolated.
Robinhood is small player that could never have planned for this type of event and likely doesn't want this. Most retail shops likely don't have the sophistication to handle an event like this.