The point it’s making is that if some colours of paint aren’t taboo for artists to use, and some combinations of notes aren’t taboo for musicians to use, people shouldn’t be so prudish as to find some words too offensive to use either.
There’s a flaw in the analogy though, and it’s not the one that’s been noticed in the update which has appeared in the post since I first saw it. Apart from, possibly, magnolia, there’s no such thing as an offensive colour of paint, but when colours and brushstrokes are combined into finished images, they could easily be offensive and often are – and the same clearly applies for notes and combinations of notes compiled into pieces of music.
But here are the analogies:
colours : images
notes : music
words : ??
It’s back to front, obviously – words themselves are the language counterparts of music and images: it’s not words but their constituent parts which correspond to colours of paint and musical notes. And articulatory gestures aren’t half as offensive as the two-fingered variety – who in their right mind would come over prudish about the occasional labiodental fricative, or uvular trill?
The poet, I put it to you therefore, assembling words from her inventory of fricatives, lax vowels, and plosives has to be just as aware of context and perceived intent in judging the (in)offensiveness of the resulting words as an artist and musician considering the raw materials that they work with. Shame, because if phonological pedantry hadn’t got the better of me, it might have even been funny.