The whole thing is strange.
2) If Google is trying to recruit people from Kaggle accounts, why not simply index the accounts?
Neither approach requires purchasing Kaggle at all.
Only Kaggle has the full data to be able to make an accurate decision. I don't really think indexing account pages is even remotely enough to find the really talented people among the noise.
I think Google acquired Kaggle for one of the following two reasons: 1) they wanted to expand their talent acquisition reach[1], or 2) they wanted to build a platform like Kaggle aimed at Google Cloud, but figured out that it was just easier to acquire Kaggle itself.
[1]: Google will NEVER be satisfied with its talent pool given their size and rate of expansion. The company is prepared to do a ton -- perhaps even acquiring Kaggle -- to get the best of the best, wherever they are.