H-1B is a problem for the immigrants labor rights not the other employees. Unionized workplaces already have strong protection against replacing workers with non union labor, including H-1B and contractors. Unless it's in a right to work state but WMF is CA based.

I agree that the system needs to go, replaced by a cheaper non employer bound visa that becomes a green card after a couple years of paying taxes. But that's not what most H-1B opponents want.