I'm looking at the USDA regulations and they seem reasonable to me. Looks like they're protecting consumers from being sold garbage labeled "cucumbers" instead of cucumbers labeled "cucumbers".
"The maximum diameter of each cucumber shall be not more than 2-3/8 inches and the length of each cucumber shall be not less than 6 inches"
Why is that reasonable?
This regulation means, that perfectly fine cucumbers that happen to be a bit smaller will get thrown away. Or well, into the lower grade category, but even in the lowest category
"maximum diameter of each cucumber shall be not more than 2-3/8 inches and the length of each cucumber shall be not less than 5 inches"
These are arbitary size regulations.
You do not need to regulate that to ban garbage. You can have a cucumber with the perfect shape, that is still garbage, because sunburned or too ripe or the plant was sick or whatever. Yes it should be illegal to sell garbage as fresh food and it probably is, but I do not see the connection to shape at all. This is merely aesthetics and personally I prefer a weird shaped ecological cucumber over a perfectly sized and shiny tasteless thing full of pesticides any day.
In all seriousness, if you’re paying by weight (or volume) then it should be OK not to have standard sized cucumbers… but pricing per unit should be reasonably consistent.