1. I can not use “DELETE” as it does a real “Reset”:
– removes all roles;
– executes original code from WordPress setup, which creates from the scratch 5 WordPress built-in user roles: administrator, editor, author, contributor, subscriber. That is “reset” means in this case – return WordPress user roles to its initial state.

So URE’s “reset” here not only deletes roles added by other plugins, but removes any changes made by plugins or users to WordPress built-in roles.

3. I fixed the link to external article too. Thanks for pointing me that.