I don't think Amar nor Charlie Palmer came off well in the drama.
I wouldn't think it fair to say that just because the other party finally regrets what happened in the past, that you would have to forgive so quickly. It's probably the first time they're meeting and they still needs time to flesh things out.
Based on the snide comment Palmer made about "no one being too good to do something (wash dishes?)", and Amar admitting that he said things he regretted that led to the fallout when he left Charlie Palmer's restaurant, I'm pretty sure that Amar had said something along those lines before. And with how he said that he used to be just like Manbun, I can see why that could've pissed off a mentor.
It's good that Amar is willing to work towards reconciliation *now*, but the other party likely needs time as well.
I think Charlie Palmer isn't so much stiff and boring, as serious and egotistical. The ego thing isn't specific to him though, plenty of chefs are - and it seems the source of their fallout was his and Amar's ego clashing.