"Quade has played 100-plus games here. He's won a title here and been much-loved. That's a solid thing, but there's many parts to this job and that's one of them. I felt there needed to be a change. If you're going to do this role sometimes there's solid decisions that have to be made."
To be fair, Cooper's axing from the Reds came not long after Wallabies coach Michael Cheika had also decided to move on, seemingly backing Thorn's judgment on the Kiwi-born playmaker's poor attack, defence and game-management in 2017.
"It's not about my imprint I just felt there needed to be a change here."
Tough and uncompromising throughout his playing days, Thorn has clearly carried those characteristics through his fast-tracked coaching career.
From the Queensland Under-20s to Queensland Country and swiftly to the helm of the shambolic Reds, it sure has been a swift rise for the former All Blacks lock.
Thorn is refreshingly honest and realistic about everything from his coaching experience to expectations. There's no grand predictions - more a sense of the unknown.
The 43-year-old always loved a challenge. That's why he returned home to the Highlanders in 2013, and stuck it out for a second season after winning three of 16 games in the first year.
Of all the mountains Thorn has scaled, from NRL to Rugby World Cup glory, the Reds must surely rate as the steepest. Over the past four years they have won 16 of 62 games, churning through three coaches in that time.
Now Thorn, well aware Australia's Super Rugby coaches could not muster any wins from 26 games against Kiwi opposition last year, has a two-year contract to spark some transformation; to start the long road of taking Brisbane back to its rightful place as a stronghold of Australian rugby.
"Things had been battling here and the board approached me. I can either feel frustrated about it or I can step up.
"I don't know how I'll go as a coach. At the very least if it's not a success I'll leave it in better hands for the next guy. I'm not a career coach but I had a career I'm trying to protect. I'm here contributing, just like I always have, everywhere I've gone. I'll give my best effort and then whatever happens, happens.
"Ideally, you'd probably have a five-year apprenticeship or pay your dues but the opportunity is there and those sorts of challenges are something I don't mind. I'm enjoying it but the rubber hits the road in a couple weeks so we'll see where it's at.
"Maybe it's good, maybe it sucks, I guess we'll find out won't we?"
Sacking Cooper and Frisby aren't the only changes Thorn instigated. Veteran loose forward Scott Higginbotham has been installed captain, replacing Samu Kerevi and James Slipper.
More importantly, Thorn is attempting to impart values based around work ethic, intelligence, efficiency and being willing to make sacrifices. All of which he harnessed in both codes.
Above all else, though, Thorn wants the Reds to fight. He wants them to care.
He wants to rid the easybeat circle drawn around them at the start of each season.
"I want to see this team compete. I want to see some tenacity and heart. It will embarrass me if fans walk away and say 'they didn't put in' or 'they gave up'. That would be very hard for me.
"It's not always winning. There's been times I've been proud as when I've lost but I gave it everything I had."
Without Cooper and Frisby, Thorn will rely on the unproven Hamish Steward, Jono Lance and Ben Lucas to run the cutter but he now has a young squad he can mould, just as he did at the lower levels. That doesn't guarantee success by any stretch but if passion and conviction counts for anything, the Reds may eventually rebound under his guidance.
"I felt something needed to be done so I'm having a crack."
