If you are driving a foreign car with a foreign drivers license, you will go to jail, whether or not you have insurance, until the damages are assessed and YOU have paid. That goes for even if you are not at fault, you are still at fault. Driving in Mexico is AT YOUR OWN RISK. Even if you get the insurance, is not what is it like in the U.S. In my opinion, if you get into an accident, you had better speak Spanish, know someone (having a Mexican police officer as a best friend) or be prepared to run back to Belize.
The point of view of the article you posted, has to do more with the Northern border between Mexico and the U.S., although it gives good advice for renting a car in Mex. Here in Chetumal, you can bring your Belizean-license plated car into Chetumal quite casually, with no importation permit. You can also drive anywhere in Quintana Roo, up the Cancun-Chetumal corridor and even take the vehicle over to Cozumel on a ferry. You can not take your Belizean-plated vehicle to Merida as it is in another state. My opinion on Mexican insurance and the Mexican government is that if they were serious about Belizean vehicles needing insurance, the insurance places would be open on evenings, holidays and weekends. Belizean insurance does not cover you in Mexico.