rofl at Cambridge
Podrick, I've just given a first class mark to a student with SERIOUS dyslexia. The essay was by far the best of the bunch and was much more carefully presented than 60% of the other ones...
In my - and doubtless most - universities now, dyslexia is taken very seriously. Students with a statement get extra support which includes more time for exams, additional learning aids (recording devices, coloured films, even notetakers if necessary). They all have a raft of stickers which they have the choice of placing on their submitted work, notifying staff. We are not necessarily more lenient with these students but we do allow more 'interpretation' of what they are saying etc.
There are also (in my place) student support services who work on writing and reading skills etc to support dyslexic students.
It is not a barrier to good results.
Laziness and not turning up to a single lecture or ever reading ANYTHING so you have no idea how to write IS on the other hand.
And the mocking thing - I would only ever do it anonymously, always salve my conscience by offering lots of detailed feedback to them, and anyway, when you've marked pages of drivel, it's the only thing that keeps you sane!