Wasn`t it a sign/symbol of extreme respect she wanted to show?
More like common courtesy (US southern style which is more like Poland than either is to mainstream US norms). IME I'd say adding "miss" (pronounced 'mizz') before first names was more common than adding mr before first names..
Similarly, in a lot of the south you'd never answer a question with just "yes" or "no" (unless you were common) the correct forms were
"yes sir" "no sir" "yes ma'am" and "no ma'am" (no comma because there's no pause)
For more well off families (which liked to name kids after elders) 'young' or 'old' might be added before mr or miss...