Light mode is the best and I think a significant number of people who oppose it are students or hobbyists who only program outside of typical work hours. During work hours, I want bright light to keep me alert. And I work in a well lit office and home mostly during the time of day when there's lots of sunlight. Dark mode just doesn't make sense for professionals.

Plus, if even a single documentation site or Google search uses a light theme (and many do, especially by default), you risk blinding yourself with the sudden flash to light. By comparison, if I'm using light mode and something else is in dark mode, it doesn't hurt me at all.