Whether he was right or wrong, he has hurt the company. I think he is wrong to be sure. But it doesn't matter.
It is also interesting because, a loss in a major legal case may throw up interesting possibilities in the stock market. Of course, one needs to be much more legally aware, than I am, to take full advantage of these possibilities.
However, Damore did file a NLRB claim before he was fired. So he seems prepped to sue, or perhaps to negotiate a private settlement.
Without a lawsuit: DOL gets two million "records" (emails/docs/memos) related to hiring/performance evaluation/etc. It needs to sift through those two million records trying to find the ones that support its case.
With this lawsuit: author knows who in the organization deals with this exact issue. Those people probably had emails from their managers/sent emails to others that can be made to support governments position in DOL lawsuit. Now instead of sifting through the two million records that they got, DOL focuses on 20,000 records authored by those likely to have the kind of information.
That's why such dismissals are dangerous to the company engaged in a costly/high-stakes litigation with the government.
Government's problem in this case is the same kind of problem that government had in the US v. IBM: IBM buried government in the paperwork and government did not know where to look at to dig itself out.
Here comes the author who seems to have a very good idea of the remediation programs that Google has. The odds are extremely high the people in charge of the remediation programs/diversity programs/etc are the ones who are familiar with the issues that Google has: it is fairly logical. The author probably knows who these people are. He probably talked to them. Probably those people told him whatever he used as the basis for his manifesto. If he drags those people out into the spotlight, the government would suddenly have a beacon for their case.
That's why I, personally, think Google made a gigantic mistake firing the guy.