Newbie here.
I think a lot of problems arise because the Arduino requires knowledge of 'C' for programming, knowledge of a computer for interfacing and running the programs and also knowledge of electronic components (and especially fundamentals such as the relationship between voltage and current) for external circuits.
The arduino attracts people with an interest/expertise in one or two of these subjects but not usually all three. This results in some apparently stupid (to some people) questions such as: "how much voltage does an LED need?" *
If people took the trouble to learn the basics of all three subjects before taking the plunge, they could ask questions in a more intelligent way. Obviously this isn't gonna happen and there's a lot to be said for "learning by doing", so we have to cope with such questions. (In my own profession, I have built up an FAQ list and I simply point the questioner to the relevant FAQ, which explains what he needs to learn. No need for a rude response - just "please read this".)
*This may seem to be a perfectly reasonable question to someone who doesn't understand how an LED works. But it's rather like asking: "how much diesel fuel does my petrol lawnmower need?"