Horse Collar tackles weren't outlawed until the 2005 season.http://www.youtube.com/watch?v=OlX4QjupoSA&t=3m41sLeaving the Clifton hit out of it for a minute, I am still shocked at how most people gave Sapp a pass for the dirty play that tore up Jerry Rice's knee in 1997.
Is this it? Do you mean dirty as in it was a horsecollar tackle after they were outlawed? It's clear Sapp was sympathetic to Rice, so we can assume he didn't mean to injure him. Still unacceptable, since horsecollar tackles were pretty front burner then and widely known as dangerous plays.