Can zoning rules be changed retroactively? And even if this is allowed, can zoning rules be put in place with the goal of booting out a specific business? I think ex post facto prohibitions only apply to criminal laws, but in general I think we disfavor targeting individual businesses with legislation.

For background, I live in a neighborhood where the property sizes are much much smaller than the rest of the zoned area. So we have to get exceptions for many things because the rules were written for properties that are 10x to 50x the size. I wish that rules could be written to cover every possible eventuality, and I personally feel the pain because they cannot (I have to pay for every exception and variance in the approval process). So having seen how rules are blunt instruments, I have some sympathy for folks who are caught up in the process.