Propose a completely different dash, which is not even on a standard keyboard!

Why does he propose a completely different dash, which is not even on a standard keyboard! The normal dash is “-” and this is completely correct, and what it proposes is probably present in some Unicode Operating System. In each forum they write also such dashes, and this one is probably from Cosmos, although I know that there are many different dashes. But in this case it is not correct.

Sprawdzanie w języku: polski…

  1. Wiersz 1, kolumna 8
    Komunikat: Spacje wokół dywizu (w przeciwieństwie do myślnika) są zbędne: najlepszy-tak; jeśli to miał być myślnik, to należy napisać najlepszy — tak. (wyłącz regułę)
    Proponowana poprawka: najlepszy-tak; najlepszy — tak
    Kontekst: Jestem najlepszy - tak mówił.
    Sprawdzono. Liczba znalezionych potencjalnych problemów: 1
    Jak udoskonalić program LanguageTool

- U+002D hyphen-minus The standard ascii hyphen. Sometimes this is used in groups to indicate different types of dash.

— U+2014 em dash The em dash is used in several ways. Primarily in places where a set of parentheses or a colon might otherwise be used, it can show an abrupt change in thought or be used where a full stop (period) is too strong and a comma too weak. Em dashes are also used to set off summaries or definitions.

In many languages, such as Polish, the em dash is used as an opening quotation mark. There is no matching closing quotation mark; typically a new paragraph will be started, introduced by a dash, for each turn in the dialog.

The not correct one (The em dash —) that you are referring is actually the right one, but it is indeed rarely used due to the difficulty of usage simply.
We decided to prefer using the correct dash characters even if those are rarely seen and used commonly online. You are free to deactivate this rule if you wish to not see LanguageTool proposing you to replace your dash character.