It is the word "rescheduled" that Easy seem very fond of using. The EU legislation does not recognise the term "rescheduled" the only options are either delayed or cancelled.
Maybe the carriers do see this particular law unreasonable, but there are laws that I see as unreasonable but that does not mean that I can ignore them. Indeed I gather that it is a criminal(?) offence to continue to ignore a law.
I, and a number of others, will be progressing our claim through the courts if necessary.
Indeed it is interesting to note that this is not the first time that Easy have had staff hour problems with the flights to Prague. Useful further evidence that this problem could have been foreseen as it has happened before.