Personally, I think a lot of people use retard too much on this site. I work with kids with developmental and intellectual disabilities and the term retard to me is saying that a person is too stupid to learn or can’t progress/improve themselves. The kids I work with try their best every day, and they do learn but it does take them longer with a ton of repetition. If you don’t like someone’s argument, then call them ignorant, unreasonable, foolish, ridiculous, witless, etc. Or better yet, don’t insult them and work on your own counter arguments.
Furthermore, if you have to call someone retarded because you can’t understand their arguments, then you have already lost the argument with your ad hominem attacks.