I saw some reviews critique why it had to take place in a specific time and place. I felt like it was a good decision to make it a period film.
But seriously, if the film wasn't in 2002 Toronto then it would have had to be set in some vague modern time. Now obvious Pixar does that well. We don't know or care when most Pixar movies are set because they don't really matter to the toys or bugs or fish. And the people Pixar movies don't really need a time period. Brave seems to be set in a fantasy world. Coco may be grounded in a time but I don't remember because it's more about generations than time. Time didn't matter much in Soul or Up either.
But Turning Red needed to be grounded in a time because the film made a pretty clear point (and the behind the scenes doc picked it up as well), that girls' burgeoning sexuality is very much rooted in crushing on popular culture or counter-culture figures like boy bands or anime characters. "Popular culture" may be too diffuse nowadays compared to 20 years ago in which a popular boy band would be a grounding force for girls' affections. Obviously, K-Pop bands serve that function now, but I think they were aiming for a time when boy bands were more central.