For example, in English the word right (opposite of left) and right (privileges, as in human rights) are homonyms. In Spanish, derecho/a also means both of those things. Don’t the concepts behind those words predate the cross-pollination of the two languages? Why do they share this homonym quality?
Right hands became right because most people used them for dexterous tasks- they were correct. Left hands were ‘sinister’- as in the opposite of correct(more accurately: contrary/false/unfavorable. It comes from the Latin sinister which was the opposite of “dexter”,)
Charts were left-to-right in large part because most of the languages/alphabets in surrounding the chart were also left to right- Greek and Latin alphabets come to mind. (Arabic would be a noted exception. IIRC Asian alphabets tend to write top down first.)
I assume that most languages were written left to right simply because it was cleaner- ask a lefty about their troubles. Left to right and top to bottom keeps your hand from going over and maybe smudging freshly written text for a right handed person.