I get that this might be a nuanced point (although it shouldn't be), but the difference between buying booze or driving a car or getting into my office building and voting is that voting is a fundamental right. Which means that the government cannot infringe upon that right without a compelling reason (note: you may think the threat of fraud is a compelling reason, this is a legal term of art and is an almost impossible standard to satisfy - it is the highest standard in judicial review).
The same thing that may intuitively suggest to you that voter ID is so important is ironically the reason why it is probably unconstitutional: it's importance. The issue is that many poor people do not have drivers licenses, and forcing them to get one in order to vote is the equivalent of a poll tax (which is unconstitutional). If states wanted to give everyone a state-issued photo ID for free, that's probably ok. But the timing of getting them to everyone is an issue (must be done well ahead of time), and what do you do in the case where someone loses their ID? They lose their right to vote??