Alonso is very political. He is also loves numbers. He tends to support his enemies enemies and in this 2021 episode Alonso would rather Max get 1 championship that is not note worthy; meaning that it would not be tied to any record like youngest champ etc. Alonso would still be greater than him and keeps his place on the all time ladder.
Hamilton on the other hand will get 8 wdc if he wins, a noteworthy accomplishment. It is in Alonso's best interest that Hamilton does not get 8 titles.
Should Alonso have to fight Max for a title some day there will be greater dislike for Max than any other driver in Alonso's memory.
The remaining 8 races will be interesting. I can see Alonso block Hamilton even more and if required he will step out of the way to help Max.
There are othet drivers that will do this as well for Max. They are tired of Hamilton winning championships.