There are lots of technologies which can help people with disabilities use the web, including switches and touchscreens.
People with intellectual disabilities often have other disabilities too, to do with movement, hearing or seeing. They often find it difficult to operate complicated assistive technologies.
There are also technologies that web designers can use when they are making websites, to make sure that their sites work for people with disabilities.
It is often better for web designers to use these to make their sites work for people with intellectual disabilities, rather than relying on people with intellectual disabilities being able to use assistive technologies.