Because voter ids were used in the past for discriminatory reasons. Requiring vaccines to not wear a mask in a store is a huge false equivalency and typical of right wing rhetoric.
How do you suppose you mandate vaccination to enter a store without requiring ID?
the same way we mandate almost anything. by trusting that the vast majority of people are sane and rational and will follow the law. most petty laws have a very, very minimal chance of getting caught if broken.
Why does that matter? There are lots of stores that require ids to enter. Comparing stores wanting to see your id or vaccination card to the government not letting you vote is a false equivalency as has been said.
It's also discriminatory to require vaccinations to be a free member of society. Just like minorities are more likely to not have access to IDs to vote, minorities are also less likely to be vaccinated, statistically.