For example, when the moderate Japanese PM offered to meet FDR, the US refusal led directly to the downfall of that "moderate" government with Tojo becoming the head of the "militaristics" government. It remains a question as to why FDR/Hull did not further pursue this path.
As another question - when the Chinese wanted to sue for peace with the Japanese, who promised aid (money and arms) to continue fighting? [Rationale here is to "tie down" Japanese troops. From what, however?]
Many other considerations.
Which Chinese sued for peace - the Kuomintang or the communists?
Becasue PM Konoye's proposal, sent in advance, stipulated that Japan's army remain in both China and SE Asia.
From FDR's prespective this was no basis for the meeting.
You are forgeting that the Japanese refused to negotiate giving up territory they conquered in their war on China, much less their initial seizure of Manchuria. The only thing they wanted to negotiate was American acceptance of Japanese control of China. Not moderate at all.