Since I assume you are very much familiar with the sun hours that are required my males in spring and females for giving birth - how can you state that this does not affect the population?
First, I didn't say it doesn't affect them at all, but in the Uk for example most adder sites are very close/within human populated areas, with walkers, dogs, nature lovers, nature haters, farmers etc....and I still haven't heard of a case where adders are unable to reproduce because of human presence! Second, I said that photographing them should be done in the right way, which doesn't mean getting too close. Third, I don't know why you think that they are less disturbed when
you photograph them than when me (or another "nature lover") if I were to come for a walk at your spot...or maybe you have some God-like powers? On top of that, I presume you are there "disturbing" them more often than your average walker! Also, keep in mind that next time you go to Greece, or Bulgaria, or anywhere.... for some herping you are going to be that "fool" that has come at some other guy's spot to photograph the animals..and maybe gets too close sometimes! And just because it's "in the middle of nowhere" doesn't mean that it's safer to disturb them because that "nowhere" could be the only place a certain species is found in the country (or the whole of Europe).
And finally, I (and many other people) feel like you, when you have some spot that you call "yours" and it's kind of a secret and all of a sudden it's not anymore and other people visit it as well. I don't like this too, but if you are an egoist just admit it, don't make excuses with the animals and don't put labels on people that are doing pretty much the same as you do at that spot!