Why do people stick to this concept like a religion as if it's the only right way that has no tradeoffs though?
If you want a heavily designed look to your website or UI, at some point you're going to have to add annotations to your data for purely presentational reasons either because of limitations with CSS (e.g. there's no way to style the first word of a paragraph with only CSS) or because there's no semantic reason one piece of data should look different from another other than it "looks nicer that way" (e.g. adding a line break in the middle of a heading because you want a two word brand name to appear at the start of a line).
You might be able to avoid presentation-only HTML markup by preprocessing the HTML, modifying the HTML with JavaScript, using some CSS hack, excessive annotations that might never be used (like wrapping all brand names in tags) etc. but is it worth if for this purity of separating data from styling? It has tradeoffs.