The 26-year-old winger has had a solid season for Aston Villa and scored ten goals in 28 appearances for the club in the Premier League.
He has not played for the Netherlands since 2015, but there were suggestions that he could be included in the squad for the European Championship following his performances at Aston Villa.
But his name was missing when De Boer announced the squad and El Ghazi revealed he did not hear from the Netherlands coach.
Janssen blasted De Boer for lacking the personal touch and insisted that players deserve to know what they did not make the cut as they work extremely hard to achieve their goals.
He stressed that it would not have taken much time for the Netherlands boss to talk to El Ghazi and tell him what he needed to do to get back into the national team.
Janssen said on RTL7: “[It is] bizarre.
“It is very impersonal, just call. This is something very important.
“The player lives for it and hopes to get in, but suddenly receives a notification that he is not selected.
“Such a conversation doesn’t take long, does it? Just give him a call and explain your decision, he needs it.
“Give him at least the opportunity to ask something.”
Dean Smith will likely be happy to have a fit and more determined El Ghazi back for pre-season with the Aston Villa squad in the summer.