What is the relative advantage of putting something into the public domain versus releasing under an Apache 2 or MIT license? The latter doesn’t restrict anyone’s use AND establishes a public record to refute what Google is trying to do. Additionally, communications by email could be via GitHub issues and open to all to see.
Though it is a very permissive licence, this does pose some barrier to using the software. Some companies are averse to using software they need to provide attribution for, but would not mind using software that is in the public domain.
Releasing software to the public domain ensures that as many people as possible can make maximum use of it.
That's not to say it's better to release software to the public domain over using a permissive licence. It really depends on the terms under which the developer wants people to use the software.