That's essentially pointless though. They may earmark your $10 for the core mission, but that just means another $10 that wasn't specified doesn't have to be used for the core, and gets used for their political initiatives. It's entirely semantics and doesn't change behavior at all unless an overwhelming majority earmark their donations the same way.

That "unless" clause at the end of your comment is precisely the point though. Just because you don't want to support most of the things that WMF are doing doesn't mean that others don't want to. If a majority of donors earmark their donations, then they will collectively have rebuked the foundation. If a majority of donors don't earmark their donations, then they will have collectively approved of the foundation's actions.