Haj Amin is not the only one at blame

Yes, that is true.

and I didn't blame the Palestinians for him.

My mistake.

You know he was intriguing and whipping up trouble long before becoming Mufti.

Yes, he was in jail at the time that Samuel Herbert had him released and then installed him as Mufti. The Palestinian leadership said they didn't want him as Mufti because they thought he was a thug. I guess they were right.

you can't say that he forced them to riot can you. The violent outbursts of 1929 were even worse.

No. Economic considerations and fears of displacement were the reason they rioted. It was not a good thing to do. But had Haj Amin not been their leader, they might have been led to do something much more constructive as a way of addressing their very real concerns.

Herbert Samuel was acting according to official policy, which was to mollify the Palestinians as much as possible.

Actually, this is not the case. The majority of Palestinians did not want Haj Amin to be their Mufti. They were not mollified by his appointment because they did not want him. There were elections held and Haj Amin lost the elections. Had Samuel wanted to mollify the Palestinians, he would have honored the results of the elections and not defied them, installing instead, a candidate that the Palestinians did not want.