It's not a new term, and it's not used in the way you might think. It also doesn't matter the screenshots.
That is what your quote says translated back to English. The first sentence reads correct. The second sentence is nonsensical. The third sentence is missing.
I was refering to your statement of "sites have started tagging such games with the 3DCG tag so that beautiful screenshots wouldn’t mislead people"
The term 3dcg is much older than 5 years, so it cannot be that they have started tagging games with it. Started is the important word.
There might be a misunderstanding, as I understood you meant it to describe games that use screenshots from koikatsu or a similar engine. So I explained that it does not mean screenshots, but it means computer generated.
But either way, you assume there is an intention to avoid misleading. I disagree. It is just them tagging stuff into categories of 2dcg, 3dcg and whatever else they use as their pool of tags.
Stuff in the quality of those pixar animation movies are also called 3dcg. Search the internet and not your malware spreading sites, if you do not believe.
Citing sites that use the tag proves what exactly? That the term is used as a tag. It does prove nothing else. It does not prove that they started using it. It does not prove that they use it to avoid misleading. It does not even prove what they actually use it for or what it means on their respective sites.
And stop accusing people of lying. It is insulting. This is a forum. By default, all you read here is opinion, not fact. The concept of lying does not even apply in most cases. Even if you think someone is wrong. Or if you disagree with their statements.
This is about games. So let's look at the biggest game site on the planet. They have tags. They allow up to 20 tags for each game. Your sites have like 3 for each game. Those might be called tags, but they use it as category or genre. Hmm. Hmmmmmm. Seems the tag does not exist on Steam. Who would have guessed. Maaaaybe, because cg is primarily used for adult games, as proven by usage on itch. And of course 3dcg as well. And in this nieche it means, the pics are computer generated, in contrast of hand drawn. Some might even use 3dcg in contrast to 2dcg.
Since Steam does have adult games, I do not know, why they do not have the 3dcg tag. Maybe because it typically is not used for non-adult games.
Let's look at an actually respectable adult game site (and not your malware spreaders and not very legit looking sites). Nutaku. Well, you will not like this. They use the tag 3d for visual novels that have 3dcg images.
You try to make an argument of authority by citing those respectable sites that use the tag you want. But your sites are not respectable, nor important. The biggest fish in the pond, Steam, a specialiced legit adult game site and indie game platform itch that also has adult games. On all those platforms, the tags are used different from the way you want them to.
So the argument of authority is against your point of view. You can solve this, by accepting, that "tag" on those sites means "category". While on itch, it means "label". Oh and one of those sites even spells category out in the url. See?
Also, you should remove those links, as some or all contain malware ads and do not look very safe. This is open community and not a warez site.