Because of that COPPA law?
Yes. As explained in the table above, it applies to Fandom because they are in the US.
Mexico's in the US?
Fandom is a U.S company, therefore U.S laws apply.
To Mexico? Just say a simple Yes or No.
US laws apply to Fandom storing the data of everyone, including Mexicans.
Tupka217 answered you already- why do you keep re-asking the question?
The only case where COPPA does not apply is when both the user and the company are not in the USA. Fandom is in the USA so COPPA applies to Mexicans on Fandom due to Fandom, not due to being Mexican.
If its US-Based it need to comply with Coppa
This again, fellow users? @TheMcBruiser6000 is behind all that complaining (hope he understands the consequences of daring to question a law).
You don't have to participate if you don't want. Also, I don't know how you would know they are the same user.