The first part of the prompt is referring to the Edict of Expulsion in 1290.
Here's the short version of the why in your prompt.
Jewish people in England up until that point were in a unique financial position where as they got special treatment when it came to taxation and the interest of loans.
Essentially, Jews could loan people money via businesses, etc and charge interest, but the Church of England forbade the lending of money for profit.
The King knew of the Jews unique financial position, and thus unethically took advantage of them by forcing taxes on them without Parliament's consent, etc. The Jewish people were just beginning to get the short hand of the stick.
The reputation of Jews as extortionate money-lenders arose, and this is where the terrible stereotypes you hear about Jewish people today arose. The people of England (specifically the Church, too) believed and spread around nasty rumors about their financial policies. Eventually, an anti-Jewish view point spread across Europe as a whole. Some believed they actually preformed ritualistic murders, etc.
It only got worse for the Jews. In 1218, the Edict of the Badge was established. This was similar to the identification method used in the Holocaust, but the Jews had to wear yellow badges in public so you could identify them as such.
Segregation, high taxation, and just plain hate was spread for the Jewish people for the next couple decades. The King himself endorsed the rumors about the Jewish people murdering children for rituals.
The Jewish people were wrongfully placed higher and higher taxation and became more and more in debt to the king in this financial cycle of interest and debt and lies. Eventually, the King himself was in outstanding debt. It was a mess.
Left with no other options, he sought out to the expulsion of the Jews to alleviate the financial turmoil at the time. Public opinion of the Edict of Expulsion was high, and it was carried out quickly.
I hope this helped you grasp a better understanding of the subject. Essentially, it as financial problems and the backing of the Church that was the how and why the Jews were made to leave England in 1290.
