Because this is also for students, apprentices, career changers, DIY'ers and others who may be less familiar with wiring regulations or good work practices than you are. If it were purely for people who know the regs, then by definition they would not need to ask, which sort of defeats the point of asking something if you already know the answer. There is no legal obligation for a working knowledge of BS7671 to do the work being asked about in this question. The better the quality of the answers given on the forum then the more traffic it can attract with better search engine ratings which can increase its potential for prospective sponsors. Which will all help to keep the forum alive and thriving. If you enjoy the forum please do your best to make it the most helpful and useful electrical resource on the internet. Thank you
Doc H.