It was just because MarkDown doesn’t really make mathematical notation easy. The point is that with a slash, the 6 is over the entire 2(3) divisor. It’s the difference between these:
Image

You can even see that the automatic solution (in yellow) parses the two differently. In the first example, it correctly resolves the 2(3) first. But in the second, it parses the 6÷2 first, because it is left ambiguous.