[nickcarraway]

Maybe people don't realize Mexico has been an explicitly anti-Catholic country since it was founded in 1821. The Constitution was explicitly anti-Catholic and they didn't even change the laws to make it legal to be a priest until 1998. They didn't always execute priests, but in the teens and the 20s they definitely did. The current political party in power, the PRI is explicitly anti-Catholic, and it's been PRI for a long time, except for two terms.

So the government does not favor Catholics.

[DesertRhino]

Why did the writers of the Mexican constitution in the 1800s feel a need to restrict the RCC and then move to codify it further into law after the revolution?
What explains this perceived need?

They had 300 years of RCC in Mexico to look back on. So what made them think it was a threat? Benito Juarez was for it, and he was a pretty decent and fair minded man.