Despite calls from critics that Beckham has not deserved to play 107 caps for England and that he is not in the same class as leading games player Bobby Moore (108 caps), Ferdinand doesn't understand the criticism of his former teammate.
"I don't understand why people argue against him," said Ferdinand.
"It's just because it's Becks. He has become such a big personality in the entertainment world, so people think he doesn't deserve it.
"He's been through five or six England managers, so he must be doing something right.
"There's no taking away what Bobby Moore was - an icon of English football who lifted the World Cup. Becks going past his record will not detract from that.
"He has had ups and downs but always seems to rise above the negative stuff," added Ferdinand.
"The fact is David is a top player. If he wins the league in Italy he'll be the only player to win the title in the three biggest leagues.
"He was part of a team that won the treble at Manchester United. He went to Spain and won the league there and with England he was the main reason we went to the World Cup in 2002 with his performance against Greece."