I would say, the enemy of music was might loosely be called the spirit of business. One had better use the word in its pristine sense of busy-ness. It does not mean primarily the direct desire for gaining money, which is a feeling that animates the most dissolute of gamblers. Rather, it means a persistent, hour-to-hour, devoted, rational application to a progressive task, a self-denying, calculating dedication to a perpetually growing achievement--not necessarily a lofty one--a suffusion by the feeling that "we are here in life for a purpose." The life of purpose can readily be directed toward handicraft of commerce: its fruit then would be money. But the money that came from this steady, alert industry would not be a mere gratification of greed or opportunity for indulgence; it would rather be interpreted ethically, as the just and visible reward of good behavior. A man, for instance, who got rich and richer by making felt hats relentlessly and intelligently for eighteen hours a day for forty years could then fix a self-satisfied gaze upon his wealth as the sign of God's approval of his intelligent relentlessness. It is clear that, to a mind of this set, music or any other fine art must be a thing of doubtful worth. The time spent in acquiring skill on an instrument is a "waste of golden hours." Music in itself may do no harm, but overfondness for it might lead a young man to spend too much time in taverns where he might overdrink, or in theatres where he might associate with loose women: all that would distract him from his busyness.
Loesser is, of course, talking about men here. Women (at least of a certain class) could devote their time to playing without compromising their usefulness.