Yeah, I've tweaked cannon a bit, but I think Sentinel needs to know just how bad organic's have had it sometimes.
"Earth needs our help, Sentinel. It doesn't stand a chance without us if Megatron decides that there's more Allspark fragments here," Optimus Prime argued.
"The Great War is over, Optimus," Sentinel said, "We need 'bots back home and working the space bridges. This backwater mud ball doesn't know the meaning of the word 'destruction'…"
"Excuse me?" Sari butted in, finally having enough of Sentinel Prime trash talking her home world. His argument with Optimus had been going on for at least half an hour. "Just how many mechs did this 'Great War' kill?"
"That does not concern you, organic," Sentinel said rudely.
"Just answer my question," Sari said.
"Yeah, Sentinel, just how many 'bot's died in the Great War," Optimus supported.
"Uh," Sentinel sighed in annoyance, "I think about a million mechs were off-lined. Is that right Optimus?" Optimus nodded.
"The the Great War, here on Earth, took several million lives," Sari said.
"Well, organics are fragile," Sentinel said, "If something get's out of control, it's not that difficult…"
"BS! wars aren't supposed to kill that many people. And then there was World War 2…"
"War World the second?" Sentinel asked confused. He wasn't concerned about how many organics had managed to kill each other, but he couldn't deny that deny that he was amazed at how quickly such a weak form of life could start up fighting again so soon after such high mortality.
"We call it World War Two, but anyway: six years, any many more millions died. Six million died in the Holocaust" Sari nearly spat at Sentinel.
"Well, that wasn't all planet side, right?" Sentinel said, showing his full ignorance of human culture and history.
"Sentinel, let it be," Optimus said, "You really don't know how bad this world's had it."
oO0Oo
"Ungrateful, filthy…doesn't know what she's talking about…" Sentinel mutters as he paces across the floor of the Elite Guard flag ship.
"What is wrong, Sentinel Prime?" Ultra Magnus asked as he entered the cabin.
"The organic," he pompously demands, "Is denying the sacrifice that hardworking Autobots made during the war."
"Have you tried to correct this misunderstanding?"
"Yes, but she still denied it. She…" Sentinel starts.
"Then that is enough," Ultra Magnus said, "It's no use wasting our time to teach one organic child our history is she does not want to know,"
"Yes, it is simply that she tried to lesson the dignity of those who died by trying to compare it with the millions that shed blood in some wars they fought."
"Millions?" Ultra Magnus asked.
"Yes," Sentinel answered.
"I would like to know more about this," Ultra Magnus said, and excused himself. He transformed and drove to the Earthbound Autobot base.
oO0Oo
"So what was this 'Great War' you told Sentinel Prime about?" Ultra Magnus asked the young human girl, bending down so that he could talk to her eye to eye, so to speak.
"Well, some guy killed a Duke…"
"Duke?" Ultra Magnus asked, unfamiliar with the word.
"The one next in line for leader," Sari went on, "Well, some guy killed a Duke, and because there were so many alliances all over Europe, and keeping the alliances were directly related to a nation's honor, everyone went to war with each other. They eventually burrowed into trenches and shot into each other until the other side gave in."
"And what where the consequences?" the Magnus asked.
"Well a lot of people died. Millions," Sari said, "And Germany elected this really evil guy, Hitler, I think his name was. He started the next war by invading Poland and killed six million innocent people. I'm not sure about details, but it was ended by a really big bomb. There's books on it at the library, I think."
"Thank you," Ultra Magnus.
Autobot command got a report for reform for treatment for organics later that day.
Sari doesn't know much about the World Wars, but think of it this way. She's an eight year old who lives a century/century and a half after WW2 ended and does not likely have a particular interest in the subject. Sure, I could imagine her knowing the basic story, but not all the gory details.