yes, language evolves. Now we recognise that retard was used to define people as sub-human and then to murder them; experiment upon them; forcibly sterilise them against their will and without their knowledge; deny them medical treatment (which often leads to their slow painful death); to bully and harass them; deny them employment; deny them opportunity; segregate them; abuse them; rape them.

Using the word retard against people who do not have LD is a weak insult to them, but does cause hurt to a large number of weak, dis-empowered people.

Retard as an insult is fucking stupid and lazy because it misses the mark.