They composed music for churches, and those two artists, and many more, created great art for churches. Perhaps you don't know Beethoven's Missa Solemnis, Mozart' s Great C minor Mass or Vaughan Williams's lovely Mass in G minor (RVW was an atheist). Not to speak of Bach. I went to the Accademia in Venice and saw some stunning altar pieces that must have taken months or years to produce. When you're a jobbing artist or musician, you do not produce your work for free out of the goodness of your heart. You have to make ends meet. Let not historical distance lend too much enchantment to your view. Get real, pete, in other words.