There are no green stars because stars don't just emit one wavelength, they emit a range that has a peak somewhere. If the peak is green, they also emit simila

There are no green stars because stars don't just emit one wavelength, they emit a range that has a peak somewhere. If the peak is green, they also emit similar amounts of red and blue light, and all combined the result looks white. Whereas there totally are blue stars and red stars out there, because those colors are at either end of the visible spectrum, and so you can get a lot more blue than red out of a star or vice versa.