There's really no "need" for Google to have any of this information (they wouldn't have had it if Spirit had been purchased and Google wouldn't have gone out of business as a result).
The article didn't say what Google wants to use the data for.
The data would likely have some value even with removal of all names/email addresses/employee numbers/etc -- i.e., absolutely no way to correlate any record with any other record. Even dates of hire and termination in the HR records could help identify the associated employee so, for example, those fields could not be linked to titles, performance reviews, salaries, etc in any way.
Perhaps that's what is being done but the value of data so cleansed seems pretty minimal for most uses -- but $10M is a drop in the bucket for Google so maybe they bought it on a whim even though it was going to be stripped of most of its value.
This reminds me of a customer we had when I worked at a database company long ago. This customer was almost certainly a government agency but had a bland "generic" name in a genre like "Optimized Marketing Partners" and their installation was in a brick building in Virginia with no windows and surrounded by a barbed wire fence. Anyway, they had a SQL query that was crashing the system and we asked for the query. In response, we got a few pages of fan-fold paper containing a printout of what appeared to be a very long SQL query -- but it was hard to tell because an X-ACTO (likely) knife had been used to cut out every field name, table name, database name, literal, and (apparently) expression. They left the SQL keywords, the periods between database/table/column names (which was impressive given the fragility of the resulting printout), and (IIRC) the comparison operators. It certainly was a fairly secure transmission of the information -- and in doing so it was rendered completely useless in resolving the problem. We never heard about that problem again after we requested more information -- presumably they figured out a way to express the question that didn't cause a crash or decided they didn't care that much about the answer to the question.