First of all its not entirely gone, just reduced. Its only "gone" meaning "an acceptable allowance" under state law has been stipulated.
Second, it cannot be proven until its shown the mothers giving birth to these new babies are mercury free. If these mothers were given thimerosal vaccines when they were children (no doubt) and have Hg-laced Amalgams in their mouths (for sure), you'd have to be: a.) a complete moron. Or b.) a propagandist to come to this conclusion.
In fact, there's no way you could disprove a link until many generations have been given 100% mercury-free vaccines and other toxic exposures can be ruled out.