Earlier quoted context omitted.
Silly jokes at a conference are like using a public wifi at RSA... This is a terrible analogy, and your point is incomprehensible: If you don't know your environment, you should not work in it? Then we should never, ever attempt to enter a new field (including the first time), as there's no way you can ever know what you're getting into until you're in it, and we're all still learning about each other. Permanently.
I said environment. You do not start a job 'out of the blue' (as a matter of fact, it is impossible). Environment, just the environment. Please, please. I know my words are hard but... The analogy is terrible why? Running risks is risky whatever the risk.
The problem with your statement is that it's impossible to know what every single person around you will find offensive. It's not a solution, because it's assuming the impossible. And when you go reductio ad absurdum, it basically boils down to everyone never saying anything to anyone for fear of offense, which is clearly not the desired goal.