A non-response from someone may be a bitter pill at times, but we have to remember that some men are not at all used to having women approach them. Even if he likes the idea, he may not have formulated a way to respond.
Think of it this way: email and online situations are easy to get into and out of. Think of that on and off switch on your tv, and how easy it is to use. We simply do not have one's full bodily attention via email and online, so we cannot invest our full heart into it. On the flip-side, we may meet people that we would not have otherwise ever met!
What is so much more difficult, is a non-response in person!
e.g., when your neighbor doesn't return a short greeting.
Jacqueline, you are very perceptive and have an intelligent and compassionate grasp on this matter.
It has taken me awhile to come to grips with responding to someone whom I believe I have no interest. I still have problems with empty emotes, short of responding with another empty emote. I'm still working on this, but I do agree, at least in principle, that all communications deserve some kind of reply.