First, no longer accommodate Harry Elizabeth II. When Harry and Megan were alive, they had already announced their separation from the royal family, but they also reserved some treatment for them. Charles succeeded to the throne and decided to put justice above family loyalty. He doesn't want to tolerate Harry's behavior any more. Because Harry is so immature and naive, he always likes to do impulsive things, so the royal family can't bear it, and decided to start work on Harry.
Second, Harry and Megan showed their love at the Queen's state funeral. Harry is particularly rebellious. He always likes to do things that embarrass the royal family, regardless of the royal image. Even during Queen Elizabeth's state funeral, he showed his love in front of the public. Many people said they could not accept Harry and Megan's behavior. Harry has done some amazing things since his mother died, so it is normal for Harry to be kicked out. Charles succeeded to the throne to rectify the royal family. If Harry hadn't been attacked, it would be difficult to convince the public.
Third, Charles wants to show his ability. After the death of Queen Elizabeth, Charles was under great pressure. Charles is very old, and the public has a bad impression of Charles. Therefore, Charles wants to show his ability. Only in this way can Charles be persuaded and win the support of the people. Charles has always had a headache for Harry. This son is very rebellious and disobedient. Charles has been putting up with him. Now Charles didn't want to put up with it any longer, so Charles began to discipline his son. Charles wanted his son to know that he would pay for his rebellion. Not only Harry and Megan were kicked out, but also their children were kicked out.