The debate over the use of parallel fifths begs the question, the cultural side of music as a language. As an analogy, some writers are considered to be unskilled because they don't use what some pundits would call "correct grammar". What some might consider "bad" writing, others would find emotional meaning in their work.

The same thing applies to music when it attempts to regulate harmonic rules, most of which today are outdated. Open fifths in harmony applies to traditional Appalachian folk singing harmonies and to the shape note hymns which break all conventions in standard harmony.
In short, music theory applies to cultural values and the original musical theory stemmed from early church edicts which have never been established as being accurate such as the so-called "church modes" which is used to classify folk tunes.