If you're dealing with lengths, you can get input data in meters, centimeters, millimeters, inches, feet, etc.
If the input data is human heights, would you automatically assume meters even if the input data is "183"?
If the input data is the weight of humans, would you always assume grams, even if the input data is "75"?
It depends on the circumstances. It might be the least bad thing to do. Or not.
But that wasn't my point. I replied to this:
> I can assume the length of a meter or the weight of a gram
Sure, the length of a meter and the "weight" of a gram are both standardized. (To be very picky, "gram" is a mass, not a weight. The actual weight depends on the "g" constant, which on average is 9.81 m/s^2 on earth, but can vary about 0.5%.)
So if you know the input is in meters, you don't need to do any further processing.
But dealing with input text files with an unknown encoding is like dealing with input lengths with an unknown unit.
So while UTF-8 itself might be standardized, it is not the same as all input text files always being in UTF-8.
You can choose to say that all input text files must be in valid UTF-8, or the program refuses to load them. Or you can use silent heuristics. Or something inbetween.
It is not.
https://en.wikipedia.org/wiki/Mars_Climate_Orbiter#Cause_of_...
Write all software like NASA needs to do for spacecraft?
Let me know when anyone has developed a web browser to those standards.
More to the point, what situation can you think of where guessing measurement units is a good idea? In a CNC machine? Maps program? Somewhere else? You seem to have omitted the actual counterargument part from your counterargument, while adding a hearty dash of misplaced outrage.
(yeah, my only grip with SI, but it's a frustrating one.)