"I'm dirty on myself in regards to not coming down harder on the boys on Wednesday," he said.
"We didn't train well. I'm a stickler for training and practising to perfection and we were very, very poor. It was the worst session we've had since the off season, from day one.
"I'm disappointed with myself I didn't come down harder on them and correct it there and then. We played exactly that way [we trained]. I'm just disappointed in myself for not getting to the bottom of it there and then."
When asked what stopped him, he suggested the media criticism he cops for supposedly being cranky was a factor.
"I'm trying to keep a happy camp, I'm trying to keep everyone upbeat. I come down too hard on people and blokes like you [in the media] come out and say I'm too cranky, I'm too tough on players. We have got a happy camp, we've got a great vibe in the joint. That was very unfamiliar to what we're about," he said.
He refused to blame the tense upset win over the Storm the week before for producing the crash-back-to-earth loss.
"I don't get carried away with a win. I like the boys to enjoy a win, they've got to, they've got to have some down-time," he said.
Both Stuart and Raiders captain Terry Campese expressed extra disappointment that the side failed to give hooker Glen Buttriss happier memories of his 100th NRL game.
"I'm very disappointed for Glen Buttriss, who's a real good bloke. He doesn't deserve to have a 100th game like that," Stuart said.
"What we dished up for him is unacceptable. I'm disappointed for him to have that for his 100th game. We're a better football team than what we displayed in that first 40 minutes today."
Campese said the side had had a couple of good wins this season, such as against Melbourne and South Sydney, but hadn't backed them up the next week.
"As a squad we have to be a lot better. Our attitude wasn't on in that first 40 which is disappointing. Like Stick (Stuart) said it was Buttsy's 100th, it was a good opportunity for us to be more consistent and climb up that table," he said.
"I'm disappointed to be a part of that. We're going to New Zealand next [in Round 10] and if we turn up with that same attitude it'll be a long day again."