The qualifications for special education teachers in Ontario involve one online course, which is supposed to qualify a teacher in “all exceptionalities”: this includes giftedness, which is not a disability. Nothing more is required to be qualified to teach special education in Ontario.
A paper examinting alternative curriculum for students with intellectual disabilities, noted the following:
Reliance on separate curricula in separate spaces for students with intellectual disabilities has led to minimal preparation or expectation among general education teachers to teach these students. With special educators in short supply, this means that many students with intellectual disabilities are taught by teachers who are less qualified than their general education teachers.
Amy Hanreddy, Daniel Ostlund – Alternate Curricula as a Barrier to Inclusive Education for Students with Intellectual Disabilities, International Electronic Journal of Elementary Education, January 2020, Volume 12, Issue 3, 235-247
In our experience, the most successful teachers for students with disabilities are those with an interest and willingness to support ALL students and be creative in their approach. There is no guarantee that a special education classroom is such a teacher.