I think the bulk of that 30% is people who either were issued a birth certificate at birth and no longer have it, or people who were never issued one, such as citizens born overseas, not in a hospital, etc. For those who can obtain a replacement birth certificate, costs are usually about $30. Poll taxes are illegal in the US.
You haven't established that those without access to their birth certificate aren't citizens.
These laws are requiring citizens to pay $30 for documentation to vote, in cases where an original birth certificate was issued but lost. Poll taxes are illegal. Of course there's something wrong, here.
Voter ID is solely useful to provide a barrier to young people and minorities who wish to vote. It's not an insurmountable barrier, but every barrier placed means less voters. Since these groups tend to vote Democratic, Republicans are attempting to win elections by preventing people from voting. This was admitted on camera in Pennsylvania.