You can learn songwriting like you can learn to play an instrument....doesn't mean your going to be great at either...but you can learn the technical/theory side of anything i guess.
I'm a chef and i work with people that have learned to cook...but! you can see they have no inner creative spark,,,they put ingredient x on ingredient y , because they have been taught thats what you do.
If you examine the lyrics section on any forum....you will read the same sort of uninspired ,mainly sad/happy/love based 'stories' or really odd lyrics about all sorts of things,,,
So really,song writing becomes a gift, when a songwriter can put words into such a perspective that it touches the soul
.sounds a bit poncey...but basically i think thats the truth,,Bob Dylan ,Paul Simon,Lennon/Mccartney etc.these type of writers have that gift!