Several of people I knew in high school are not Frum anymore, and the responsibility for that is squarely on the shoulders of those who ran that site.
WADR (and, keep in mind that I am no fan of Rabbi Shapiro and Frumteens), if a rabbi on a internet message board can make you go OTD, you probably weren’t all that strongly on it to begin with.
IOW, he may have played a role, but to lay the blame “squarely” on his shoulders as if he is the sole (or even main) reason someone went OTD is far-fetched, IMHO.
The Wolf