[besselheim]

The author of the article believes that their gender cannot be categorised as either male or female (hence a "non-binary" gender), so they prefer for others to refer to them using "they" and its inflected forms, rather than "he" or "she".

The singular "they" is already commonly used when the gender of a person is not known, so its extension into non-binary genders is quite sensible, in my opinion. Some others who regard themselves as a non-binary gender prefer invented pronouns such as "xe" or "ze", but I think expecting others to remember and use these is rather unrealistic, whereas "they" has the advantage of already having mainstream use in similar contexts.