Arkansas has a good history of putting TE's in the league too, each starting TE was drafted in '15, '16, and '17. That is more than Stanford can say. That is not even including their best TE from this century, who is currently an All-Pro LT.
Stanford mainly had a decent run from the Harbaugh years, in '12 and '13.
Every kid doesn't want to go to Stanford, and they're not necessarily idiots because they choose to go elsewhere.
The kid's brother just left the school, and he was a solid TE there and was the Chargers starting TE until he got hurt this offseason. Maybe he's more comfortable being a 2 1/2 drive from home at a school that he personally knows can put players at his position into the league, than a school half-way across the country from that he can't even get a direct flight to, has ugly girls, a student body made up of dorks, and a non-existent fan base.
It certainly won't be the last time a kid turns down Stanford either.