On the other hand, in the French chart "DivD" is listed as far right when it's just a collection of non-affiliated right-wing candidates going from center-right to far-right.

The charts are rubbish. Not only it lists e.g. parties with "socialist" in their name as "centrist", but they didn't do a "left-wing" colour to begin with, so e.g. communists parties are "other". That's not very balanced...

I am also curious of the author's definition of right-wing.

For Slovakia KDH - Christian Democrats, SMK (later Party of Hungarian Community) and SDKU are all considered right-wing parties.

However, the Hungarian Fidesz is definitely a right-wing party, but not an extreme right.