This seems identical to the idea in match play golf of whether it is bad sportsmanship to not give your opponent a short putt. But in chess and golf if the win is so easy or putt is impossible to miss then just finish it. If there is some risk of failure then your opponent is justified. When you decide to play a chess game with someone your obligation for a win is to checkmate the enemy king. That you may win sooner by your opponent resigning is his prerogative, not yours.
Pretty good analogy. Not everyone concedes putts, and they aren't required to. Even the very best have missed important putts inside a foot.
One thing we would never see though, especially at the highest levels, is anyone getting upset because their opponent did not concede a short putt. No matter how easy it is, they are expected to finish it.
This seems identical to the idea in match play golf of whether it is bad sportsmanship to not give your opponent a short putt. But in chess and golf if the win is so easy or putt is impossible to miss then just finish it. If there is some risk of failure then your opponent is justified. When you decide to play a chess game with someone your obligation for a win is to checkmate the enemy king. That you may win sooner by your opponent resigning is his prerogative, not yours.