All Politicians lie. Twitter is not in the business of being a fact checker.
> Asked whether Twitter would ever consider banning key government officials or even the president himself, a company spokesperson responded via email: “The Twitter Rules prohibit violent threats, harassment, hateful conduct, and multiple account abuse, and we will take action on accounts violating those policies.” Pressed on whether that meant that, hypothetically, Trump himself could be suspended were he to violate those policies, a spokesperson confirmed: “The Twitter Rules apply to all accounts, including verified accounts.”
Twitter going out of their way to say that they might ban the US President isn't exactly a sign of the professionalism and maturity people expect from multinational executives.
Are you joking? The press would say "'...', Donald Trump said on Monday".
Anyone who can't infer the "Donald Trump said" part from the Twitter UI shouldn't be unsupervised near a computer or a newspaper.
It also encourages him to publicize views that can withstand press scrutiny. The outrageous stuff we see on Twitter might have been self censored if he had to tell it to a skeptical press that will place them in context.
Prior presidents have been very circumspect in what they say, which has reduced the pressure on this point. Extreme situations pressure us to discard gray areas. In order to maintain a healthy civic discourse, we need everyone to cooperate more and be more generous to the other side, but this can't be done unilaterally or you just get steamrolled.