I think it's just our natures to protect the things that we surround ourselves with .... especially when those things are good.
A wife will defend her hustand to the ends of eternity if he has proven loyalty to her. Let the same husband be disloyal, and the wife is ready to execute him at all costs!
When we (all) have a product that works for us, we all think the best and do our best to defend it. When the product fails, we think the worst, and usually brings out the worst in us too. It's just our natures! It's just who we are.
Whoever said "take it with a grain of salt" was absolutely correct. Good, bad, or indifferent, we have to take the advise with a grain of salt. Sift out what works for us, and toss out what doesn't.