If you love somebody and you find out that one of you might die how do you react? That wouldn't cause me to put up emotional walls so much as add the sense of urgency and get me thinking things like "If I don't tell ____ I love her now, I may never get the chance.". Isn't that just the standard human reaction to such things?
Originally Posted by THM Nindo
To add to that Naruto has always been about bonds. Friendship and love aren't so different from a practical standpoint. If one isn't avoided why would the other be?
Plus, the process of killing emotion comes at the price of humanity. The land of waves arc addressed that with Zabuza. So shinobi in the narutoverse try and control emotion rather than avoid it. Sure sometimes this leads to tragedy but to quote an old cliché....
"I hold it true, whate'er befall;
I feel it, when I sorrow most;
'Tis better to have loved and lost
Than never to have loved at all."
- Alfred Tennyson
One thing i would like to make clear is that the hormonal/sexual side of love means absolutely nothing to me as far Naruto goes because that part doesn't carry much, if any, narrative value.
The value is in the process of lovers realizing their feelings for one another, letting the audience make a part of that bond their own, and use that to reinforce the quality of both the characters and the story. Nothing draws an audience in like a pair of characters falling in love with one another.