If I replied in in annoyance, then that was surely because the tone of your original post was rather antagonistic. I note that this tone has rather calmed down now so maybe you were another who was going fishing - I had already spotted that Max Chat was; not too sure about you Psyan!!!!
Instructing/trial lessons is one thing, undertaking commercial activities is entirely another in the practical sense. The trend is not to legislate for every single variation but to do so en-mass within defined parameters.
What, in practical terms, is the difference between a trial lesson and a pleasure except in the former, the customer has the chance to operate the controls. This has not bearing on the medical fitness of the pilot-in-command. You say that the trend is NOT to legislate for every single variant but the definitions of aerial work and public transport are variations. In some cases, especially with aerial work, it is not down to the nature of the work but the employment status of, say, a cameraman.
If you're 56, why don't you retire now? Is it because your pension isn't enough. That is certainly the case with some pilots and not necessarily through any fault of their own and therefore need to continue working. Why shouldn't they be allowed to if they can?
Cheers
Whirls