Why are there some views regarding Jews in the Quran that do not seem to be held by mainstream Jews today, such as Uzair (AS) being the son of God?
Those who claim that Uzair is son of God are condemned in Quran as those who claim that Maseeh (Jesus) is son of God.
Jews have many different sects and divisions in faith and we don't condemn but only those who went away from the real message of Torah and adverse stand against any prophet.
We read in Quran about the People of Book ( Not all of them are alike, a community from the People of Book stand for the right, they recite the Verses of Allah in parts of the night during prostrating to God. (Sura 3, Verse 113).
Allah (SWT) tells us in Quran to call the People of Book for common word between us and them (Say: O People of Bok, come to a common word between us and you, that we worship none but Allah and we do never associate any partner with Him) (3: 64)
Wassalam.