Why is there such confusion on air passenger rights?

On Wednesday last week my flight from the Alps to London City was cancelled.

In fairness, we all know that these things happen; particularly given the UK's current (and near permanent) 'winter monsoon' status. Instead, I was put on a later flight to Heathrow, about 2 hours to the west by public transport or about 26 miles away by car.

This would have been academic if it wasn't for the 48 hour Tube strike and the fact that I had 2 large bags and an unwieldy pair of skis to schlep across the Capital. They all weighed in at a bantam weight of 50-odd kgs. As I soon discovered, every gust of wind turned me and my skis into a human weather vane sending hoards of weary Londoners scattering in all directions on the rain-soaked streets.

On one particularly long walk, I mused on what my rights were as a passenger. One representative of my airline had informed me in Geneva—with an almost imperceptible shrug of the shoulder to suggest that she wasn't too sure—that 'London is London' regardless as to the airport. Heathrow is the same as Gatwick. Gatwick is the same as Luton. Luton is the same as Stansted. Stansted is the same as City Airport and so on and so forth. If the airline drops me off at any of the these airports then they have discharged their duties.

However, a quick glance at the terms and conditions of the airline the day after suggested that this was not the case. In other words, it had a duty to take me to the original airport (City as opposed to Heathrow). However, the airline staff themselves didn't seem to know what their obligations to me were. I wasn't too sure myself, to be fair:

• had I inadvertently waived my rights by agreeing to fly to Heathrow just before the flight was cancelled?
• was the airline obliging me to fly to Heathrow or had I volunteered to do so?
• what exactly did I say and agree to?
• what laws applied?
• is Switzerland part of the EU for these purposes? and, most importantly:
• why is this so difficult?

Indeed, the typical response of airline representatives of 'you can try to claim [x] back' (after the event) suggests to me that there still needs to be some work done in this are