The issue is, as others pointed out, that Twitter was extremely powerful for groups in oppressive countries to coordinate their activities. So much so, that some governments had resorted to switching off the internet for the whole country to combat social media; particularly Twitter.
It's entirely plausible that the supposed large sums of money that Elon received from Middle Eastern groups to help buy Twitter was for the expressed purpose to destabilize Twitter and destroy the brand. That way once Twitter is gone dissident groups can no longer organize and will be easy to oppress.