Past Trauma Influencing Characters

[aragornreborn]

Well, I had thought it was just the lure of the Ring....

Yes, the lure of the Ring was probably the main draw. But what Olorin is saying is that other factors most likely contributed to Boromir attempting to take the ring. Most people would say Boromir is a decent character and most people would say he had no ambition to become a dark lord. So he clearly isn't evil and desiring the ring for those purposes. Therefore, other things much have contributed to him trying to take the ring from Frodo, such as desiring to protect Gondor. And he probably was not thinking clearly when he tried to take the ring. Gandalf just died, Gondor is in trouble, the quest looks like a failure... Things looked pretty bleak to Boromir and his behavior could have been altered because of that. So, basically, that's what Olorin is saying.