You forgot the part about insulting people who accidentally click buffs, or ask for buffs before a MoB that mass dispels, or random tells for buffs ...
Thankfully, there is no shortage to the amount of people who will lead raids. If it's ten seconds before a Boss MoB pull and the tank needs a buff, it's too late. This is not World of Warcraft where you have every spell up at once and don't need to sit to mem a spell. Others have already listed reasons why it's both stupid (tank should be paying attention/raid leader should be paying attention) and dangerous (sitting on a pull is *BAD*, and any half decent raid leader knows this). Just because you are leading the raid does not mean you have considered every available and possible alternative and outcome. Raids are not comprised of followerbots. Individuals (at least, individuals I'd bring along on any EQ raids I led ... and there were plenty of raids I organized) are capable of having their own thoughts and making decisions. They have reasons for doing what they do, even if to the uninformed and less aware of how human beings think and act it just seems like laziness or unwillingness.
Besides, Tyrranical Raid Leaders are just unpopular sops who have no people skills and who have an army of loot hungry toads following them to accomplish their goals.
Any halfway intelligent raid leader would have replaced the tank for not paying attention to their buffs in the first place. Any halfway intelligent raider would find a better raid leader and consider themselves blessed to not be under a raid leader whose inferior grasp of game mechanics and individual roles is so laughably limited.