It sounds like I'm disagreeing with the person because I'm disagreeing with the person. I don't think that what Twitter can do and what they should do are at variance, because I don't think Twitter has a moral obligation to allow others freedom of expression on their tool.

Even if Twitter wanted to promote freedom of expression, there's an inherent contradiction between allowing others to express their opinion and them expressing their own opinion. I think someone whose promotion of freedom of expression involves denying themselves that same freedom is sending a mixed message. Because their support of the principle would have those reservations, they don't have an obligation to provide it.