Don't understand why you would like someones' profile then not communicate?

I would like to know whether there is a deep secret to the paradigm of the 'Singles sites'. What do you need to put down in your profile, apart from the truth, that will stimulate someone to respond to you. I personally seem to get 'Like' responses from 34ish very attractive women from the USA, who quite obviously are not interested in me for me, for a very good reason (1 might be genuine but there are so many of them). I am new to this activity and have made it clear in my profile 'if you're not prepared to communicate, then jog on'. I am not an unreasonable person and am patient to a point but it seems that there are too many people on these sites looking for Mr, Ms or Mrs Perfect. Just my thoughts but if I am totally wrong can someone please explain to me why anybody would engage in the singles scene just for the sake of it!