There are several synonyms for the phrase "often injurious aficionados," including "reckless enthusiasts," "hazardous devotees," and "dangerous supporters." These phrases all imply that the individuals in question are passionate about a particular subject or activity, but may engage in behaviors or actions that can cause harm to themselves or others. Other possible synonyms might include "risky enthusiasts," "detrimental fans," or "unsafe followers." These terms all suggest a level of enthusiasm and dedication, but also indicate that caution or moderation may be necessary to avoid negative consequences. Ultimately, the choice of synonym will depend on the specific context and tone of the piece of writing.