Retard has two uses. If you're talking about watch mechanisms or dough in the fridge the word retard is perfectly fine, no-one cares about that use.

The word retard is hate speech, linked to actual real world violence. And that violences is very common.

https://www.mencap.org.uk/sites/default/files/documents/2009...

> A survey by Mencap of people with a learning disability has found that nearly nine out of ten respondents have experienced bullying in the last year. Two-thirds are bullied on a regular basis and almost one-third are suffering from bullying on a daily or weekly basis. People with a learning disability face prejudice and widespread discrimination that often makes them feel like outcasts and prevents them from taking a full part in society. Public attitudes in the United Kingdom towards people with a learning disability remain discriminatory. The Mencap survey suggests that the bullying of people with a learning disability is institutionalised throughout society.

How they described bullying:

> The following behaviours were most frequently cited: kicking, biting, name-calling, teasing, stealing, pushing, threatening, having things thrown at you, being told to leave a building, hitting, being shouted at, swearing, demanding money, hair-pulling, throwing stones, spitting, poking, being punched, being beaten up, having one’s head banged against the wall.

I did not contest the facts. But not using the word retard won't help any way. They face prejudice and discrimination because of their condition, not of the way said condition is called. And if we change the word with other - the other word will still be used as an insult. Because the condition itself is highly undesirable. No one wants to have it.

But simply not wanting to be inflicted with a condition is no excuse to dehumanize people who are. Perhaps part of the problem is simply people mocking eachother for being different, but another part of the problem is the cultural normalcy of abuse promulgated by linking diagnostic terms with definitions of global inferiority. Language is the very matrix from which thought arises, so real-world usage of words can alter people's perceptions.