The actual game does not have undos.
In-person games don't have misclicks, either. The original game does not present you with a situation where you have 3 Magpies in hand, planning to play all 3, and, after playing the first two, your hand re-renders and you accidentally click on a smithy, ending your actions for the turn before you get to play your third magpie.
The original game is played at a far more deliberate pace. A single in-person game easily takes 3x as long as an online game, and part of that is attributable to the speed with which the players make their plays. This is going to lead to some misclicks in the online game, and to situations arising (as above) that simply would never occur when playing in person.
way to fully mitigate against such accidental misclicks/misplays is to play the online game at the same slow, deliberate pace as in-person games. That appears to be your preference, and when I find myself matched against people who prefer this style of placing for an online game, I oblige. That's not poor sportsmanship on my part; it's smart play, sizing up my opponent and adapting my play accordingly.
Yes, you can chose to reject all undo requests out of hand. I can view you as a poor sport for doing so. We'll have to agree to disagree, and hope we never match up. (I have a pretty mediocre rating, so I imagine that won't be much of an issue; I clearly take all of this far less seriously than you do)