Here's specifically why:
I get a name of a shadchan and call up; there is no answer, I leave a message and try calling back 3 more times to follow up with the same answering machine to leave my voicemails. As a new name, I was hoping to actually speak with new-said shadchan but why bother even giving people their number when they cannot return a call?
Second situation this week-I call up a shadchan who I communicated with before. The answering machine now states that if this is for Shidduchim, please don't leave a message-better to call between certain hours. Guess what? No one answers during those hours-trust me, I've tried.
Third such occurrence. I met a few shadchanim who, even though we've met in person and spoken by phone, have mentioned to me that they prefer communicating by emails only as it's easier (for whatever different reason they each gave) for them. So, in respect to their requests, I send a gentle email asking if they can please be in touch with me, etc. Oddly enough, even though I know the email address was spelled correctly and did send properly, not even ONE of those "shadchanim" replied. Not a 'thanks got ur email" or even a "sorry didnt reply, was busy/out of town/ lost my phone" or even something to say "have u in mind but don't have any guys YET". Not even a courteous 2 words.
So these people call themselves "shadchans". They give out emails and phone numbers but don't care to answer either their phones or emails. Their voicemails kindly ask you not to call them so why bother?