It’s a notorious freak moment in daytime television. On Sept. 13, 1978, one of the three competing bachelors on “The Dating Game” was Rodney Alcala, who turned out to be a serial killer; he was captured the following year. (He was convicted of five murders, though it’s believed that he may have committed as many as 130.) It’s no joke — or maybe it’s a meaningful one — to say…