It is no wonder that people get so upset with you for the statements you make. Unless you are an influential member of the Jetstar board (which I know you aren't) you cannot possibly be able to state that this deal WILL be there in Feb 2014.
Has the airline proven in the past that this price guarantee is renewed at it's expiry? Yes they have - but that doesn't mean it will continue. What if the new brokerage between Qantas and Emirates means they need to change that offer?
You just don't know. You make statements - like the one above (and others such as 'Eurofighter!') which are only your assumptions or presumptions. You then get extremely defensive when you get called on it, and argue the point as if it was a certainty.
In some cases, you make some really good assumptions that turn out to be right. In others, you lay claim to the knowledge of the gods that makes you the butt of many future jokes (Mack Restorations anyone?).
When are you going to learn that all you need to do is to phrase yourself a little differently, and you'll irritate people far less than what you do currently - and perhaps might earn a little respect.
For example, a better way of phrasing the above could have been:
"I wouldn't worry too much about the June 2013 cutoff date. They've had these in the past and so far they've extended the offer every six months. They might change it, but it's still very possible that it will still be there for you next february"
just cover or qualify your statements a little better - thats all most people on here want from you.