That doesn't really matter. Anyway it's silly to question whether Google, a multi-trillion dollar company, can validate someone's ID when they already do it in many other aspects of their business.
But is Google treating some claims different from others? Are Ellie Piee's claim against Gergely Orosz's article, and the latter's appeal treated exactly the same as any other? In other words, if I use an obviously bogus identity to make DMCA claims against Google content on their own platforms, will they immediately take it down and then go through the same standard appeal process? If not, then the system isn't "abused" it's used exactly as it was designed to be used. In an asymmetrical manner to the benefit of some.
So the real question isn't "how can Google validate an identity", it's "why is Google treating some different from others"? It sure isn't an accident.