I would not say you was too much of a mug to of taken out this deal! When you took this deal you accepted it, was happy with it, and assumed your situation would not change, or at least change for the worse.
I think it is fair to say that every single person that takes out finance falls in to the above statement.
i also took out the same deal as you in 2011 on a brand new 1200gsa. How ever, from my humble calculations (and i am stupid) i worked out that the 'scheme' is poor in the sense that you can only truly walk away from the deal, when at the end of the term you give them the bike back and walk away with potentially nothing. And after paying all the money you would do for the term. But at least you can walk away at the end without spending more money.
I took the deal because i wanted to keep my repayments low during the term. Then at the end if i have the money to pay it off, which i had planned to, i would and get a great bike. if i didn't have the final payment, just give it back. Its cost a lot of money but i had a good time with it.
My previous bikes were all jap bikes. I bought a vfr800 nearly new, and traded it in 2 1/2 years later. For what i 'lost' (or the cost of having fun on it) i would have to keep the gsa for at least 4 years for it to be 'as cheap' as the vfr.
The only other way of course was if i had got to the end of the agreement, didn't have the funds to clear it, i had the option to just trade it in and get another. Ofcourse, this time round i would have to up the term to keep the monthly repayments the same. This i feel would of been a silly thing to do, and really highlights the fact you can't actually afford it. As really you are only increasing, and deferring, the inevitable loss. As the max term for the agreement i think was 3 or 4 years.
I personally feel this scheme is excellent on the cars, for people who are given an allowance from there employer for a company car! But again, as seen in the op, if you change or loose your job, you could be heading for a loss.
How ever not relevant this is to yourself, i would not say you were a fool or stupid to of taken out this deal. if things had worked out, as no doubt you and all of us plan, you would of bought the bike at the end, and would have the capacity to of sold it with 75k miles on it in 10 years time. Then, including the cost of the finance etc, it would of been a cheap (as it can be buying brand new toys) deal!
If we all didn't plan on things working out, or at least hoping that things wouldn't go totally tits up and the worst possible outcome become realistic, then non of us would have mortgages etc and the world would not turn!
It sounds to me (and i am not trying to assume your situation) that a lot of factors have all converged at once and had a bad outcome. I really hope you get sorted out matey.