Me personally? I’ve become much less tolerant of sexist humor. Back in the day, cracking a joke at women’s expense was pretty common when I was a teen. As I’ve matured and become aware to the horrific extent of toxicity and bigotry pervading all tiers of our individualistic society, I’ve come to see how exclusionarly and objectifying that sort of ‘humor’ really is, and I regret it deeply.
Retard is not a medical term, it’s an insult, plain and simple. Retardation is a medical term but always paired with a specific biological function, not aimed to label an entire human.
You can also say someone’s obese, depends on the scenario and tone used. If it’s not germane to the current conversation, you’re being a dick. If it’s intended solely to bring someone down, you’re being a dick. Even if they’re being an asshole, find another retort, there are nice obese people you’ll offend in the process. Pretty much any scenario where you want to say “fat fuck” but thought you could get away with saying “obese” instead, you’re being a dick.
It’s really not that hard. This is why some people can “get away” with saying certain things, they’re saying the same words but with clearly different intentions.