They can. They just need to pay a little more. We’re talking 25 pence per liter at most compared to no sugar tax. Higher sugar intake is correlated with obesity which means more health problems which is more expense for the NHS. It’s like a train ticket or gas taxes or taxes in general, some percentage of usage that causes the problem needs to pay for the thing that deals with the consequences or expenses that solve it.
It’s the companies who have decided that they would rather sell shit soda, and consumers who are probably unwilling to pay anything except the cheapest price possible - wealth inequality and poverty problems aside because that’s a different social policy that should not be addressed through a sugar tax.
The midwest has always been pretty centrist at least within living memory, usually split right down the middle. It only ever gave the impression of heavily republican leaning because they've been gerrymandered to shit. Wisconsin in particular has been ratfucked by redistricting - both a democratic governor in 2018 and Biden in 2020 won because those are state wide votes, but as of 2022 the state legislature is 66% republican while only having won 53% of the popular vote in that election.