In any country where voting preferences are strongly correlated with education (like the US, where it's particularly strong, but this effect exists in most places to some extent) you'd expect this sort of thing when looking at a company that generally mostly hired highly educated people.

_Age_ is likely also a factor. Google's employee base would be younger than many companies, but in general employees of most companies would be likely to vote more for the left in the US than the general population, because people above working age are more likely to vote for the right.

The only care about diversity as a tool to further their own agenda. Countless examples of big tech attacking or ousting diverse people who voiced their own opinion that was contra to the narrative.

I dont know why you think the overall donation rates of an entire company of employees is the same thing as the voting rates of individual employees. The article notes that Eric Schmidt is one of the largest donors that are included. The article makes no claims as to the relation to amount donated per employee who even bothered to donate.