How is this a mistake and not a blunder?

#12 I do agree with you to some extent. Here my nuances.

Putting all the evaluation eggs in one engine basket, may already be lopsided as sole automatic feedback expected from a user, and almighty truth oracle. But not providing alternate or adjustment to that automatic treatment may be contributing to not seeing the subjectivity around such notions as mistakes, inaccuracies, and blunders. I would even question making any degrees of mistake scale... if one size fits all were a hardware constraint. leaving further gradation to the humans involved.

The attitude being too serious or not, may depend on the attitude with respect to the game just played.
Also, whether in general the person being wanting to measure the game among other games, with a competitive outlook over many game in a small range of time, or alternatively, wanting a measure over a game that has been played with some thinking at least few spots throughout, and wanting to extract the most out of one game. It might even be that there was some debating withing the game either one-sided, or openly between opponents. Some move may actually have been experimental decision in the context of new visible ignorance or hesitation in plans implied by a few move alternatives. That investment of time, might be better rewarded with a corresponding adjustable framework of feedback.

There seems to be a few parallel threads touching this subject, with different examples and sub-focus, and I made comments there that might also apply here. And I suspect many interested posters here or there have been doing the same. No complain, just a note that some ensemble view might help. ... somewhere.... don't know how.

My fun is debate the c..p out of anything. To be accused of being too serious is always a surprise. What is being too serious, is the importance given to the engine blunder call feedback too much. Or is it the one size fits all assumption, not acknowledging the various chess ambitions across chess enthusiasts.

So yes it might look like a storm in a glass, given some assumptions of motivations on the individuals wanting feedback.

#20
14...c5 is a mistake (?) as it gives white a protected passed pawn without compensation
39 Nc4 is a mistake (?), that throws away the win achievable with 39 Nc8
40 Qh5 is a mistake (?) that loses the game

@DidISeeACheckmate move 37 and 38

So, we have one person who focused on mistakes, the other on the blunders. See how important it is to differentiate the two?

#12 and #21

If you are giving up the points because you know that there is a huge advantage, then yes it is a moot point. But you have acknowledged the advantage.

If you have made a move thinking it was the best move and completely "blundered" a rook giving up 10 points, then it should at least start there.

It could be, "Yes, it was a blunder, but..........." then the reason ("I wanted to get to a quicker endgame" for example).
Or, "OMG I missed that blunder, why didn't I take the rook?"

yes

#24
A mistake (?) is a move that either turns a drawn position into a lost position or a won position back into a drawn position.
A blunder (??) is a move that turns a won position into a lost position.

#27

I disagree. A blunder should also refer to subsequent moves. Chess is not 100% positional.

There is also the psychological, emotional content to "blunder" because of its meaning outside chess.

www.merriam-webster.com/dictionary/blunder
blunder: noun: a gross error or mistake resulting usually from stupidity, ignorance, or carelessness.

The usual meaning in chess for blunder is "a very bad move". Yet I've had some students who convert that into "I made a blunder, hence I'm "bad". Depending on the student, I avoid the word "blunder" completely.

People have been arguing over how to annotate chess games with such words and their glyphs for centuries. With computers we at least have the means to allow people to define them as they want and to change automated analysis to mark up the game per the user's choices.

[Edit: By the way, I have no emotional issue with "blunder" in a chess context and I consider the point count loss in #1 and my example of hanging the Queen both blunders; meaning very bad moves.]

Either you are increasing the breadth of the definition of "mistake" which waters down the meaning, or you are possibly making a "bad" mistake into something even worse sounding by calling it a blunder. Perhaps, there needs to be a new word. How about "oversight"?