Section 88 of the Criminal Code states: "Every person commits an offence who carries or possesses a weapon, an imitation of a weapon, a prohibited device or any ammunition or prohibited ammunition for a purpose dangerous to the public peace or for the purpose of committing an offence."
So an air soft gun can certainly qualify as an imitation of a weapon, especially to the uneducated eye.
However, you may have noted that either the journalist because he wanted to edit his piece, or the cops because they wanted to make a point outside the purview of the law as drafted, left out the word "purpose" from the accusation. This actually requires evidence of an intent to use the imitation weapon for a dangerous purpose to public peace. That intent will be hard to prove, as merely showing up somewhere with a weapon for a legal purpose yet causing concern in some citizens is not sufficient evidence of intent.
In short, the mere effect caused in some citizens is not proof of intent in and of itself.
I suspect that the charges will be dropped quietly once a defence attorney gets involved.