I don't believe 'signatures change' is reasonable or valid. By the time someone reaches adulthood and has an ID, their mark is likely to be quite distinct. Check your grandmother's signature sometime. My point being, that dismissal is not evidence or fact based, but likely aligns with your opinion.
>ultimately up to the counter
There's absolutely no reason to do that. Digital files already exist of all signatures and the envelope is coded to each voter. The comparison can be done trivially by image processing.
I have my own signature that I can check and I KNOW it has changed significantly over time. Why? Because I don't sign a lot of things! Hell, I hardly write anything down.
There are many, MANY, reasons a signature can change, for example, injury. But beyond that, there's just general drift in the way people write things. [1]
> The comparison can be done trivially by image processing.
No, it can't, because the signature is not exact, even in the best of cases. The software HAS to make allowances in differences and once that happens, we are in the territory of "what is this actually proving?"
Further, signature forgery is a thing. There's a reason banks and CCs no longer even check the signature. It's a relic that proves nothing.
But beyond all this conversation, the current process for states doing signature validation isn't to reach out to the person that cast the vote to verify their ballot, no, instead they mark the ballot as invalid and move on. [2]
Indeed, if the concern was voter fraud, why WOULDN'T you want to reach out to the absentee ballot caster to find out if they actually cast the ballot? Why would "throw it away" ever be the right move?
[1] https://www.thecut.com/2016/09/why-your-handwriting-keeps-ch...
[2] https://electionlab.mit.edu/sites/default/files/2021-07/swif...
Otherwise, I agree with your point. The reason ballot harvesting is much less of an issue than made out is because there's a vast paper trail with each mail in ballot cast.