> Though in general, each business may decide with whom they wish to deal, there are some situations when a refusal to deal may be considered an unlawful anti-competitive practice, if it prevents or reduces competition in a market.

So based on your own link, "refusal to deal" has nothing to do with this situation since stifiling the posts of world leaders is not anti-competitive, in fact, it creates a competitive opportunity for platforms that might offer better service to those users.