I don't play golf to any high standard, but when I put a marker down on the green and replace the ball, I know whether I'm putting it down in the wrong spot, certainly to the degree shown in the video - I'm right there looking down at my marker, after all, so I don't need 4K TV. I would imagine a golfer who does this thousands upon thousands of times would be able to replace a ball more accurately than I am. That there seems to be little gain in wilfuly misplacing the ball in a competition so closely examined, I can't comment - could be a momentary lapse of concentration, pressure, or even intent - only she can know. However, it seems obvious to me that it's reasonable that she should know she placed the ball down in the correct spot, or in this case, not. So given that she should have known and didn't assess a penalty on herself, the extra two shots for an incorrect scorecard seems fine as a penalty for her having not scrutinised her own actions closely enough. Removing that second penalty from the rules seems to only encourage people to try and get away with not scrutinising themselves enough.
After that, the argument seems to boil down to whether we want the sport to be so highly regulated at competition level that every golfer has an official with them at all times in order to improve 'watchability'. Even then we'd probably argue about the individual officials, just as we do in other sports, and instances would arise, just as in other sports, where the official was incorrect in their assessment. Where do we draw the line in the sand then?
As the official in question is quoted, she couldn't ignore an infraction of the rules once it had been brought to their attention. If we were currently talking about how Lexi had won in spite of a penalty that viewers could not notify the tournament of, would we be happy?