Sidebottom leaped off the ground and collected St Kilda midfielder Maverick Weller with a high elbow in the opening seconds of last Friday night's game.
The incident forced the young Saint from the field and he took no further part in the game due to concussion.
The Magpies accepted Sidebottom's suspension on Tuesday morning, ruling out an Tribunal hearing and the risk of a four-game ban if they were unsuccessful.
"First and foremost, Steele is a ball player," Buckley said at the Westpac Centre on Tuesday.
"With the way incidents are adjudicated these days, as soon as Weller went off knocked out, the misfortune of that injury was enough to send Steele for weeks."
Buckley said the length of Sidebottom's suspension hinged too much on the severity of Weller's injury.
"Given that the AFL are now trying to legislate for misfortune...Steele could have gone into that contest with a far greater malicious intent and hurt Weller less and received a lesser penalty for a greater intent," he said.
"But because the injury is now taken into account, you can get unlucky - Steele got unlucky."
Buckley said he was clearly against the penalty being dictated by the seriousness of the injury.
"This week, less than I normally do and I normally don't agree with it," he said.
"Looking at Steele's in isolation, I think he's a bit stiff in regards to how cleanly the contact occurred and how much damage occurred in the short-term."
The Magpies will welcome back Luke Ball, Dane Swan and Brodie Grundy for their Queen's Birthday clash with Melbourne.
Jesse White will also play, despite a compound finger dislocation, while Ben Reid will line up for his first game of the year in the VFL. Buckley said Reid would need a few games back in the VFL before being considered for senior selection.
"We want him to be up and about (by the end of the year)," Buckley said.
"We've got designs on him making us better, so having him fit and firing is the first step on that journey and we'll give him every chance to get there."
Meanwhile, Buckley, like Melbourne counterpart Paul Roos, is opposed to the implementation of zones in the AFL.
Laws of the Game committee member and former West Coast coach, John Worsfold floated the idea on Monday night to help reduce congestion in the game.
But Buckley said it would make the AFL "absolutely" unrecognisable.
"I'm just getting around my son playing under-8s, having to wear wristbands to stay in the forwards, mids or backs.
"That works really well for kids. I haven't spent much time on it, but it's good at under-eights level."
