A web developer knows his field.
But someone interested in security knows this field even more with it's bottlenecks and quirks.
I am quite sure NPT has a lot of interest and experience in both fields, but I also suspect he's got some good experience of marketing.
But, experience alone is nothing. As the mods already said here, he uses his common sense.
If people did that a very tiny little bit, I assure you everyone could be termed "expert" by that time.
But as some say, it is weird how
common sense is not so common 
.
Edit: On a second thought, I think I know why they sort of attacked you back. You have to see how you word your sentence otherwise it looked almost like an insult.
Of course, from a normal perspective, that would not be. But people here are quite vehement, and the mods are more then prepared to fight back (of course in a civilized manner).
On the other hand, I don't think your question should be openly discussed and especially because it is beyond the point of this topic.
Next time, ask the member (NPT) directly through a PM.
(wow saying that feels like some mod

)