I have no idea who he is to you. For all I know that could be your neighbour's name. But generally speaking in hockey circles, he's known to be the GM of the Nashville Predators
He drafted Tolvanen in 2017. Tolvanen spent years in the Nashville system including many games in the NHL. If it was obvious that Tolvanen was an NHL player, wouldn't Nashville be the team that should be aware of that?
Poile acknowledged his mistake
Predators' Poile: Waiving Tolvanen 'could be a mistake on our part'
You might consider that sometimes these things aren't so obvious. If they were, somebody in the Nashville system should have pleaded for him to not be put on waivers. If it was really obvious, no one would have needed to plead in the first place.