The point is that Dutch has a lot of features that is shared with both low German and Scandinavian languages but that has disappeared from modern standard German, not that it has always been more similar to low German than to other German dialects.
E.g. like low German and most of the other West and North Germanic languages, Dutch did not go through the High German Consonant Shift, but modern standard German "imported" that.
That makes modern German a lot harder to read for Scandinavians in ways that Dutch simply isn't.
I often find it easier to read Dutch despite never having learnt it than I find reading German despite having had three years of German lessons in school.
And if you start digging into the shared vocabulary between Dutch and the Scandinavian languages, you'll find a whole lot of those words are words that have retained far more similarity to the low German dialects than the Scandinavian languages have to standard German.
See also my other comment on this, with some comparisons.
Note that this does also not necessarily go both ways - I'm totally willing to accept that you might find high German more similar than low German from your perspective because of different subsets of shared vocabulary or structure, for example.
E.g. like low German and most of the other West and North Germanic languages, Dutch did not go through the High German Consonant Shift, but modern standard German "imported" that.
That makes modern German a lot harder to read for Scandinavians in ways that Dutch simply isn't.
I often find it easier to read Dutch despite never having learnt it than I find reading German despite having had three years of German lessons in school.
And if you start digging into the shared vocabulary between Dutch and the Scandinavian languages, you'll find a whole lot of those words are words that have retained far more similarity to the low German dialects than the Scandinavian languages have to standard German.
See also my other comment on this, with some comparisons.
Note that this does also not necessarily go both ways - I'm totally willing to accept that you might find high German more similar than low German from your perspective because of different subsets of shared vocabulary or structure, for example.