Yes, perhaps. Chibi is invented in order to make content with small children "okay". I know it's explained in another way, but yeah. Same as all the games with 20 year olds who look eleven.
In most western countries, just making a game character seem underage, regardless of the explained age, is a criminal offense.
So I feel that's a bad choice to make for a game like this, even though the characters seem adult. That just makes it stupid to do chibi.
The chibi form has evolved from what used to be known as "Super Deformed", where originally, it was used to get around graphical limitations of early consoles. Of course, one of the side effects has the character looking "cuter", but in no way does it depict them as children.
Lets take one of the most recognisable characters in gaming history, Chun Li from Street Fighter. Over the decades that Street Fighter has been around, there have been times where Capcom has needed to get around graphical limitations and thus has used the Super Deformed, later Chibi, style.
Have they de-aged Chun Li?
Have they made her a child?
No, because that's not what the art style does. The implication is simply the character is the same age, they're just smaller and cuter.
This is not just a Japanese art style, its been used more frequently in Western media, in particular, Animation, often as a punchline for a joke.
Another example, this time from one of the biggest brands in the world right now, Marvel.
The youngest characters there, Spider-Gwen, is about 19. Given they're showing several characters who have not appeared in the MCU but rather the comics, we can also say that Spider-man is probably in his mid to late 20s. The oldest are Captain America (over 100), Wolverine (over 120) and Thor (thousands of years old). Not one of them has been made a child or is being depicted as such.
Look, the game clearly states that the characters are over the age of 18. You might not like the chibi choice, that's fine, but there's no need to imply this is suddenly illegal. Besides, I'm sure there will soon be an in-game menu option to not see them.
