But that is not what happens. They can be purged for being legal and not voting, or moving house, or having the same last name as a felon or a dead guy or a million other reasons.
Too often that surname is Washington or Hernandez.
And illegal voting has not been 'shown' by the Texas attorney general. He made the allegation with no evidence whatsoever, as demonstrated in the Snopes
fact check I posted earlier.
Actually the snopes article made it clear that there was insufficient data to know how valid or invalid the concern is. I think for any reasonable observer there is insufficient proof (from what we know) to determine how significant the data generated is; it is certainty a potential problem, given what data is available.
One reason for the uncertainty is the somewhat vague descriptions of the methodology and the distribution of the years of each persons non-citizenship, subsequent registration, and voting record since that date. Naturally, if a person is a non-citizen in January and registering to vote in May, he/she is far less likely to be a legal voter than someone who was a non-citizen in 1996 and registered in 2001 or later (even if their DL was never updated).
It is also unclear if the federal database is generally kept up to date, or if it is ever consulted after the original date of the DL or ID. As for surnames, common names appear more frequently in the records because they are more frequent in the population, and therefore should be found in greater numbers. Alternatively, given the current nature of politics and criminality, its not implausible that greater numbers of those with black and Hispanic surnames are there because proportionally more of them are illegal voters. And, one should note, most legal non-citizens and voting naturalized citizens in Texas are not on discrepancy lists - meaning somehow their non-citizenship DLs and IDs were corrected at somepoint.
In any event, until more methodological and empirical information is forthcoming, its impossible to make any conclusion one way or the other. And none of this need be a controversy if so many did not fight relentlessly against every effort to confirm that a voter is, in fact, a legal voter - which non-citizens, illegal aliens, and felons (usually) are not.
The purge lists may not be the optimal method, but until a voter ID or DL is issued in accordance with either a birth certificate/naturalization documentation requirement (real ID?) this is one of the alternatives.
If you think it worse than a robust voter ID then it may be a case of not being careful what you wished for.