And that's illegal?? They did the equivalent of fuzzing the system.
You've got an axe to grind - sorry, I don't. I don't know Musk beyond the limited amount of news I bother to read about him, don't own any of his products, don't use any of his services. I have no experience with him at all. Just another Rich Boi with toys, the world has plenty of them now. His drama is hot-swappable with any of the other Rich Bois who think their money buys them power and accommodations.
So, does Musk have a point to his complaint? Simply, not from where I'm standing. Again, if the algorithm didn't allow it, it wouldn't / shouldn't have been possible. Is Media Matters dirt-digging? Sounds like it, but also sounds like they were quite successful; X has been receiving multiple complaints for a long time about their [lack of] proper hate speech filtering, and maybe MM has caught them out, not unlikely as (remember) Musk did lay off thousands of workers when he took over, making these kind of things more likely.
What will happen from all this? MM's point is, hopefully, to simply make X be much better at their much-promised hate speech filtering. Maybe MM will be seen as guilty of something or not, I personally don't have enough detailed information (do you? The media hasn't given that level) to make a judgement. All I know is how computer systems respond, and a system won't respond unless it is either built to allow that response or caught inside a coding bug. But it seems YOU already have made a judgement, 'damn lefties' and all that...because, what, poor X is a target? Doesn't that identify X as a favorite of the *right*, maybe making MM's point for them? Reconsider your stance and question, are you seeking the truth or too placed within your own propaganda bubble to know the difference??