You are stating the obvious; we all know neither actually matter if a bear is, in your stated scenario, charging you within 25 feet. Not for anything, you are absolutely not drawing, presenting, and acquiring irons period with a bear charging at 25 feet; you are pointing and shooting instinctively. Let's be realistic, I dont think im talking to Jerry Miculek here. You'd be lucky to have your hand on your pistol by the time he's 10 feet out. Frankly a pistol period very well might not matter at that point either. Dot or not.
...but if you have time and space there is zero question the red dot is better once youve learned how to shoot with it. If the dot makes one of two situations better, isn't a detriment to other, and only requires some practice in the living room to learn how to acquire it...I'll take the dot.
To each their own though, do what you feel is best for you. I was only offering some advice on how to become proficient with acquiring the dot.