Hi there!
Anti-modernization means that some people don't like the new and modern ways of doing things. They prefer the old and traditional ways instead.
For example, imagine that there's a new way of cooking food that involves using a microwave. Some people might not like this way and prefer to cook their food on a stove like their grandparents did.
Or let's say there's a new way of communicating with others using social media. Some people might not like this and prefer to talk to their friends face-to-face or on the phone like their parents did.
So, anti-modernization is when people don't like the new and modern ways of doing things and prefer the old and traditional ways instead.