No Irony. He admits his education was imperfect. The complete para is :
"But though I was none the worse for having neglected exercise, I am still paying the penalty of another neglect. I do not know whence I got the notion that good handwriting was not a necessary part of education, but I retained it until I went to England. When later, especially in South Africa, I saw the beautiful handwriting of lawyers and young men born and educated in South Africa, I was ashamed of myself and repented of my neglect. I saw that bad handwriting should be regarded as a sign of an imperfect education. I tried later to improve mine, but it was too late. I could never repair the neglect of my youth. Let every young man and woman be warned by my example, and understand that good handwriting is a necessary part of education. I am now of opinion that children should first be taught the art of drawing before learning how to write. Let the child learn his letters by observation as he does different objects, such as flowers, birds, etc., and let him learn handwriting only after he has learnt to draw objects. He will then write a beautifully formed hand."
If Gandhi says 'Bad handwriting is a sign of imperfect education.' Evaluators correcting the exam papers may think anybody with a bad handwriting is a poor student discarding the content of what he has written.
Sometimes people just go by the trends. Times have changed a lot since Gandhi. These days non-violence is taken as a sign of cowardice, during Gandhi's time it was considered a sign of perseverance, patience and taking on the enemy with moral courage and ultimately defeating him by mere Kindness and courtesy.