I think you don't understand what has happened here. OP's wife has a DUI in the USA. Canada does not normally allow people with a DUI into Canada. In exchange for $250, they allowed her in. This is both a surprise and a nuisance for OP.
It sounded to me like she paid her US fine and thus ceased to be a scofflaw. After further reading it looks like convicted criminals can apply for a temporary residence permit for CAN $239.75.
This may not be needed if 5+ years have passed without further misdeeds and may apply to be deemed rehabilitated.
This covers individual evaluation of your case and may be denied. It probably also serves to keep the riff raff put especially Americans who otherwise may take a day trip to share their further drunken driving adventures with their least lucky Canadian friends.
It is hard to contextualize this as a bribe with poster as a victim when the very reasonable alternative is simple denial.
You have no right to visit Canada and they can charge you as much as they please and its your responsability to do your own homework as far as travel requirements.
