The paper reflects on public discourses about science and pseudoscience, proposing the same discursive structure for both--the Esperantist-Epideictic genre. This genre of discourse might bring together characteristics that we understand as constituents of the public discourse on science. It also enables us to depict the process by which to maintain cohesion on a group's values. The discursive activity points to science as neutral, free, and independent of social influences captivating those already in this discursive sphere. The discursive hermeticity appears in the Esperantist content and the Epideictic form by avoiding the dialogical situations where there is no epistemological and axiological dispute. We thus, show that the Esperantist-Epideictic genre helps to understand the process of maintaining a cohesive group whose beliefs about the Flat Earth appear in social media. We use data from three sources: transcriptions from seminars held at that 1st FlatCon Brazil, most viewed videos on YouTube where affirmationists talk about Flat Earth, and semi-structured exploratory interviews conducted at FlatCon. Our findings indicate that some conceptions of validation of knowledge, scientific method, science bias, reality, and truth compound a distinct part in the current conversations about the Flat Earth movement. Moreover, the Esperantist-Epideictic genre of discourse can be an analytical tool for framing the echo chamber in social media while defending or attacking the Flat Earth movement. We conclude that in a time where there is a growing consensus that science is under attack, the ways in which its defenders are trying to stand up to it may be causing some harm.