Frank Stella like Jasper John thought that painting should be viewed as it is as a whole, independent from what it is trying to represent. The individual hand painted brush strokes although there being 12 in the same sequence on each piece are unique. It is this repetition of the same action that give the abstract expressionist piece its charm. Same action different outcome every time. The lines are not perfect but neither are they too messy or do they fall out of the rules set by the artist.
Stella is rejecting metaphorical associations and symbolism that may suggest spirituality. This is rather different as art is seen as an expression of self and a means to express ideas and symbols that would correlate with others emotions.
The painting is what it is.