While the strike may or may not constitute extra-ordinary circumstances... the cancelling of services such as flights to GVA 3 times in the last week, which is not run by the striking cabin crew, is nothing other than on economic grounds by BA.
Likewise the person fro TPA who was delayed his ticket was from TPA to LGW if i read the post correctly... The whys and wherefores of the delay to the inbound aircraft are not relevant IMHO.
This just puts up a smoke screen. If the airline does not have a turnaround schedule that takes into account such non exceptional happenings then it is their fault it they can not provide that which they advertise and sell very happily, and should be made to pay.
If the EU261 had been thought out better it would have mandated an ombudsman service to receive all requests and decide who was to be paid, and bill the airlines directly while paying the claimants directly, and not allow the airlines to fob people off.