I don’t think they’re saying there’s only two groups, just trying to contrast liberalism and the left, since the two terms are often used interchangeably even though there are significant differences between them. Of course it’s more complicated than that, there’s a lot of nuance and not everyone will fall entirely into one group or the other, but I think it’s useful to show why the left doesn’t always side with liberals, and vice versa.
I don’t think they’re saying there’s only two groups, just trying to contrast liberalism and the left, since the two terms are often used interchangeably even though there are significant differences between them. Of course it’s more complicated than that, there’s a lot of nuance and not everyone will fall entirely into one group or the other, but I think it’s useful to show why the left doesn’t always side with liberals, and vice versa.