You also have to bear in mind that John Major despises Thatcher with every fibre of his being, as she basically did everything in her power to screw his premiership, and kept meddling in Govt business when she was out of power. That and her uncanny ability to say one thing and do the opposite especially over Europe. She was a master of spin, and started this whole PR ran political mess we are in now.
Thatcher backed him hoping he was going to be a puppet, and do her bidding when in power, and when he didn’t the notorious Thatcher malice and bitterness was brought to bear.
Read the book I posted a link to, its a dry but very informative potted history, of her political career.