That is the claim of double world champion Mika Hakkinen, having already denounced Briton Hamilton's "sub-standard behaviour" in the Principality last weekend.
"I appreciate Nico's patience in this situation," Hakkinen was quoted by Finland's Ilta Sanomat newspaper.
"I do not like the idea of what Lewis did," he added, referring to Hamilton's accusations of sabotage and his refusal to congratulate or even look at new championship leader Rosberg after his back-to-back Monaco win.
Now, Hakkinen is not sure even time can ease the tension between the two Mercedes drivers.
"It's hard to tell if something is going to change significantly," he is quoted in his latest Hermes column.
"I don't know if Lewis would even consider apologising for his behaviour. It is a very individual thing.
"But in my opinion, one of the characteristics of a good winner is that he also knows how to lose," Hakkinen added.
The former McLaren driver, who retired in 2001 and is now 45, was at the grand prix last weekend, where Hamilton suspected Rosberg deliberately ruined his qualifying lap.
Hakkinen is not so sure.
"To me it is clear he locked his brakes at Mirabeau," said the Finn. "It is downhill there with nasty bumps and so making a mistake is easy to do.
"Nico is an honest guy," Hakkinen added, "but you can also see on the computer very precisely where he hit the brakes."