Everyone has the right to express themselves, both positively and negatively. Its troubling that Marvel were truly blocking critical comments on social media. Critique censorship can create an echo chamber, limiting prospects for growth and improvement.
Any creative endeavor, including movies, need constructive critique. It enables filmmakers and studios to determine which portions of their work were well received by the public and which sections may require development. If Marvel censors unfavorable comments, they may lose valuable feedback and be unable to generate even better content in the future. If they cease utilizing politics in their films, the detractors will go away.