We can be so logical about talking of an illogical emotion such as love. It hits us out of the blue, it makes us feel something that may be counter to what we've known, believe, was taught.
We want the benefits of it, but not to pledge to it. We give it freely, but could easily take it away and say "Well my dear, I never told you I loved you".
It's like back in eighties when it was so fashionable to say "I detest TV, and don't watch, or let in my home", now we're on-line, have gazillion channels on our TV, IPodded out, carry our phone with us where ever we go. So much for fashion.
With Jack and Ennis there was still doubt, confusion, neither really understood how the other felt, Ennis didn't know how much Jack loved him, until after Jack's death, and Jack when remembering the dozy embrace accepted this one moment was as close he was going to get to his lover, so let it be. There was a disconnect even between them.
I'm not saying use "I love you", like a get out jail free card, but let us not be so jaded that three little words should put such fear in us. This story was filled with fear.