I love all this self-righteous indignation and protesting

The CAA Safety Regulation Group published CAP 756 in 2005 relating to just this topic. It is very pertinent. Two paragraphs stand out:

"The use of Portable Electronic Devices on board aircraft by flight crew, cabin crew and passengers is common practice. Such use can present a source of uncontrolled EM radiation with the potential risk of interference effects to aircraft systems and equipment. Given that a civil aircraft flying at high altitude and high speed in busy airspace is in a hazardous environment, and given that many of the on-board systems are safety devices intended to reduce the risks of that environment to tolerable levels, then anything that degrades the effectiveness of those systems will increase the risk to the aircraft."

and

"The need to monitor for any potential human factors interaction issues, which may include personal conflict that may arise through use of phones within the confines of the aircraft cabin, may require considerable attention"

My take on this is whether we like it or not, whether we believe it or not, the rule is there and - let's be honest - is it really such a big deal to have to wait until the end of the taxi until the aircraft is on stand before turning on your phone?