"fool" in your name maybe can be a reason. As far as I know they change your player name only if it is your real name (with surname, I guess) or if it contains bad words.
There has been options to change user names due to the enforced name assignment for mobile app players. Periodically this opportunity is offered but an interested party would only see the offer on only mobile.
The restrictions on changing user names are fairly tight. We can force a person to change their user name if it is deemed objectionable. We will change a user name if it contains personally identifiable information. Some early users of the app did not get an opportunity to select a name for themselves, and we can change their names after following security protocol. All others get told it is not possible.