My mother hated it. One semester my grades weren’t good enough to stay in the Honor Society. She blamed MAD and threw out my whole collection!
My mom was a free thinker. If our grades were slipping, she probably would have encouraged us to read more Mad Magazines, and anything else we could lay our hands on.
In her mind, all reading was a good thing. In the five decades since my childhood, I've realized the wisdom in that.