A sterling example of legal fiction is what's called corporate personhood. Think about it: A corporation isn't a person. It's a business, a pool of investors' money used to conduct transactions and hopefully make a profit.
It is an assembly of persons, legally bound into a singular entity, and as such must have the same basic rights as individuals. Under the constitution, people have the right to assemble for a variety of reasons, including to conduct business. The act of assembling cannot strip the individuals of their basic rights in the course of doing their peaceful business. For example, if the corporation is sued, the corporation has a constitutional right to council, because the individuals have a right to council. If the individuals want to, en assembly, say that the President is the best President ever, or the worst President ever, then they have the right to do what
as an assembly, i.e. as a corporation.