Perhaps it is because of the abstract nature of meeting some one initially via a screen and text. I think it is about as strange as a blind date. May be it is because it doesn't seem spontaneous or romantic as say a guy chatting to a girl at a book shop and saying "hey wanna catch up for coffee?". When they recall this encounter they say " oh we met at a book shop" vs " oh we met on match.com".
the implication is that match.com means that there has been a lot of filtering and is there is more backstory in the sense of " oh did he/she match their description?"