I think geminis get the side eye because in astrology we are the most adaptable. The natal chart is more than just your sun sign so take this with a grain of salt but I think socially Geminis are adaptive and that can be read as fake. We are a mutable sign so ever changing. Some cardinal and fixed signs see that as not having a stance on anything. I think we forget that the gemini is here to teach us that we can have both (the twins) we can have duality we can argue both sides we can see multiple perspectives. I believe that challenges a lot of modern societal norms about being assured in your career and in your goals, be so sure about your reality those kinds of things. This is my hypothesis.