I fundamentally disagree with adding certain titles to the "Perfect Games" list not being optional in special cases. To me the list is, first and foremost, a showcase. It's all the games a player is passionate about and has taken the time to master and complete in the fullest sense.

If you just needed the raw information of "What games have I completed all achievements for?" you could simply sort for completion percentage and have all your "perfect games" at the top.

But if you are wondering "How many games have I completed perfectly?", the list (Or at least a counter) becomes necessary.

However! Are ALL games that only have the achievement "Start the game" really of interest when wondering about how many games you have gotten good at over the years? Or how many games you've enjoyed enough to hunt? Are games with that one achievement really games you want to showcase?
To me, personally, the answer is a clear "no!"

I do not want to showcase a game, that I only started once, in my "Perfect Games". I do not want a game that I didn't really like and that I played for less than an hour next to games like Hollow Knight, which I have played for 800+ hours and which I am proud to have completed and mastered. There are games I loved and love on that list, that I am proud of having finished all achievements for, because it meant patience, practice and building skills. Next to games that don't matter.

If I can easily google 100+ games that I could instantly add to my "perfect games", then what's the point of having that list? What's the point of a showcase if it isn't really a showcase anymore?

Do not get me wrong. I understand if a developer does not want to force people to hunt achievements and I appreciate the idea of only setting a single really simple achievement, that everybody can accomplish quickly. And I absolutely believe that it should be possible to have these games on the "Perfect Games" list! Hunting achievements shouldn't be a requirement to be allowed to proudly showcase a game you love.
But by the same logic, that a player should be able to decide whether they display those games, I also believe that it should be possible to opt out.

Taking away the option of removing certain games even incentivises developers who don't care about achievements to set one easy achievement to force their game onto the list for advertisement. I would like to be able to remove those games.

Is there any reason at all to not make the addition of these games to the list optional?
Or should the addition of any games at all be optional to the list?

FYI: I have already asked the Steam Support on whether they could simply remove said games for my account and was told that that option doesn't exist and that I should write a suggestion here.