Need To Understand This Hadith?

Assalamualaikum There is an authentic hadith in Sunan an-Nasa'i 3221 >Narrated 'Abdullah bin Buraidah: It was narrated from 'Abdullah bin Buraidah that his father said: "Abu Bakr and 'Umar, may Allah be pleased with them, proposed marriage to Fatimah but the Messenger of Allah said: 'She is young.' Then 'Ali proposed marriage to her and he married her to him." Some people use this hadith to criticize the Prophet’s ﷺ own marriage to Aisha (may Allah be pleased with her), claiming a contradiction: Why did the Prophet ﷺ reject Abu Bakr and Umar’s proposals due to Fatimah’s young age, yet he himself married Aisha at a young age