Lager, there is a big difference between making appropriate accommodations for a child who does have special needs, and allowing a child to do what they want, when they want.
I have a number of students with very different needs in my classroom and they are all managed differently. But I would not be calm, caring, capable and well, just, professional if I just allowed a child to spend the day reading books (or playing Minecraft as would be the preferred option among my students). It may mean encouraging a child during the writing activity to write about Minecraft instead of their holiday, as works well with one of my students. It may mean setting very specific targets: 'I'd like you to write five sentences, using these words, and three different types of punctuation'. Or one boy in my class who I know will need to be sent for a run around the oval in the middle of his work to give him a break. It may be a worksheet that is targeted towards their need, or it could be allowing them a choice of targeted activity, or giving them a timer so they know how much time is left. And yes, in all cases in my classes, for all students, it does mean the expectation to finish off the work that is set for them, whether it be during class or during their project time on Friday afternoon.
But allowing a child to do what they want, when they want, is NOT being a good teacher. That's a teacher who either doesn't know how to manage the different students in their care, or doesn't want to. Believe me, some days you wish you could just leave them all with their books and not have to make them do the tasks that they need to do. Setting clear expectations and manageable and achievable targets is what works best for students, then sticking to them. Many of the kids in my class absolutely love to read, but they know that in order to be able to spend some time free reading, that they need to complete the task first, then they will be allowed their reading time. They don't get to just decide that they will read instead of doing their work.