Rendering of vector fonts to fixed grid of pixels leads to incorrect results in principle. Introducing blur where there is a sharp edge in vector data is also a wrong result. You can just choose which kind of wrongs is more annoying - whether distortion due to grid-fitting or blur due to naive rendering and antialiasing.
There is no objectively "best" way to render vector typefaces to a raster, but that's not because all of the options are equally correct, it's because options that are more accurate to a font might look subjectively worse. There's nothing "incorrect" that a raster rendering of a shape can't convey the signal with perfect fidelity, but that doesn't mean that all rendering of vectors to raster is equally correct.
Like fine, let's put aside somewhat intentional things like hinting and grid-fitting with accumulating error for a minute. Some FreeType configurations dramatically fuck up the visual weight of fonts, making the regular style in a type face look fairly bold. The damn font looks wrong. It's not "wrong" as in I disagree with what the designers intended for the type face, it's wrong as in it looks nothing like the designers intended and it looks nothing like the parameters you put in to render the font. There is basically no perspective where this output is desired, it's just a bad rendering.
There's definitely a bit of subjectivity in exactly where to draw the line, but there is definitely still a line you can cross that just goes into blatantly wrong territory. The relative visual weight of a glyph is not supposed to be influenced by its size on screen.
