The first one is the wrong opinion to have, because gamers unquestionably have the agency to choose whether or not to enable achievements. If anyone is telling them that it's an essential part of the experience of retrogaming, they should rightly be discredited... but they probably don't need to be because that attitude is absurd on its face since we're talking about games that people enjoyed well before RetroAchievements and maybe even before the internet. Even if somebody wants to play a game for the first time and pick up achievements as they go, what's the problem? I'm not referring to achievement-hunting, and, no, it's absolutely not the same as modding every game. Gameplay remains original, and a thingy that optionally goes "ding, you did a thing!" every once in a while is so far from the biggest ruiner of experiencing games "properly." How about pretty standard features like save states, rewind, and so on?

And, look, I say this as someone who absolutely believes that more people should experience things for reasons of intrinsic motivation, and play DOOM without mouselook and modern lighting effects. But I wouldn't take away these other way to play, even if people might incorrectly choose it.

The third one... it's a weird choice for a developer building a tool, who presumably cares about community feedback, to say no to an overwhelmingly popular feature. But that's certainly their choice, just as it's the choice of users to eschew the project in favor of one that has the features they want. Imagine a developer leaving out support for keyboard input because the "right way" to play any game originally released on home consoles is with a gamepad, or somebody saying that DOOM should only run in DOS on a 386.

I went down this road in our conversation because you asked, but this wasn't even my original issue with the article. It was the unfair strawman arguments that the author brought out to throw shade on achievement developers, to the point where the author had to invent naive or nefarious motivations for doing so. Some choice quotes:

What gets me so often in retro gaming is the desire of some to "repair" the past. (...) These players see old games not as art existing in a different context, but games made in a time where we just didn't know any better.

There is an infuriatingly naive hubris to the idea behind them. We'll fix the past by importing one of the mistakes of the present.

To draw on the abilities of rom hackers, backend developers, and emulator developers, tens of thousands of man-hours, all so a Shroom joke can appear when you pick up your first Magic Mushroom in Super Mario Bros.

Do you really want someone who stares at a hex editor all day design achievements and write jokes for a game released 40 years ago? Designers who think The Legend of Zelda requires a special speedrunner overlay, with intrusive UI elements, a timer and enemy kill counter which exposes secret mechanics to new players.

They cannot look backward. The old things they loved no longer adhere to the standardization of the modern day. The self directed play of older games might as well be seen as barbaric.

Simply the least charitable, lowest empathy, most intellectually dishonest takes for throwing shade at some volunteers making stuff for other people.