I feel like regardless of the reasons they did it, whether or not it was necessary, they lost a lot of good faith with the users when they locked the GME and crypto trading during that whole thing. I have no idea how necessary their actions were but regardless of its necessity it still cost a lot of user good will.
this is a good example of the importance of comms and user education. robinhood didn't lock trading - or at the very least, they were far from the only brokerage to do so and had very little choice in the matter. however, they were the front end that uninformed users experienced it through and thus took a huge PR hit
And it's not like they did not have other options -- they could have posted more collateral, and given that they raised billions soon after, it was within the real of possibility for them.