1- The Qur’an says من المهاجرين “from the Migrants.” The word من in Arabic has numerous meanings, just like in English. Here “from” means some of them, not all. It doesn’t say all of them. So the word من solves the problem
2- Look at verse 101. It says Medina is filled with hypocrites and so there were people from the Ansar who were hypocrites. Verse 100 definitely does not praise them
3- A person may be good then he deviates. As long as he is supporting Islam Allah is pleased with him. Later if he deviated he loses this status. Many companions lost this status.
4- There were early migrants who apostates and left Islam. Um Habeeba (who later became the Prophet’s wife) migrated to Habasha (Abyssinia) with her husband. Her husband became Christian there and she separated from him. So does verse 100 include her husband? Sunnis accept that he became Christian. It’s not a disputed matter.
Verse 100 is about those companions who were early migrants or helpers and stayed firm in their faith—not all of them.