I believe Cullen is expressing a longing for freedom from the passions and pains of life. To live is noise, is being pulled constantly in different directions. Cullen identifies wisdom with letting go; in death we let go, finally, of everything.
If you consider the good and the bad in life and you are not sure if one outbalances the other, then you might a lot of death credit at least for ending the bad. It’s a wash.