False equivalency. Even Dorsey admitted in a Vox article a couple years ago that his company leans so far left that right leaning employees fear to express their opinions. Twitter has been uneven in its application of rules for quite a while now, and I admit this as a left leaning person! I don't believe in censoring opinions I disagree with just because it benefits those with whom I agree.
A company policy is not dictated by the personal opinions of its employees, many companies have a series of audits and separation of control to prevent corruption and biased. I don't know that twitter does, but I don't think it is fair to say that because the employees of a company are left leaning the organization is.
I believe that twitter censorship policies are far more about optics and what is more commercially viable for the company.
You can bet the reason they didn't ban the president for the numerous policy violations is because he is driving traffic and engagement on their platform.
That isn't to say that certain employees won't overstep bounds and act on personal feelings, but that doesn't mean twitter as an organization is leaning left or right.
Corporations lean in the direction of profit, far more than moral or political leanings.
I mean, its real easy to get hyper focused on a specific instance and start making claims like that.
But I think if you take a step back, they have let a lot of dirt swing from both side, and in the face of overwhelming pressure from the public have started to be more restrictive on this sort of propaganda as the election is coming up.