I disagree with him to some extent, writing lyrics for a song can be the same as writing poetry, that is why some poetry notably KipLing and C Fox Smith work as songs ,because they are written to a rhythm, whether you think Kipling was a good poet or not is not the point, the point is that poetry can be the same as song, and the proof is that Kiplings poems work as songs
So it depends on the style of the poet as to whether they work as songs,
Dury may have been a good lyric writer, but that does not mean that his opinion quote
"writing lyrics for a song was not the same as writing poetry" is one hundred percent accurate.
Whether i take the statement at face value is not an entirely a subjective opinion, if it was, there would not be poems that work well as songs