The less protection/controls something has, the more right-leaning it becomes. Any Internet forum that allows anything to be posted with little moderation is a good example of this.
It only seems like websites/Social media is left-leaning because there have been invisible controls blocking right-leaning content for years.
Can you clarify the type of right-leaning content you are referring to? I would not expect comments such as “we should lower taxes and reform entitlement programs“ to be subject to censorship very often.