As a 'rule of thumb', should we ban offensive language?

A US university's list of offensive language includes such phrases as 'as a rule of thumb,' and 'picnic.' Is this wokeness gone mad?

According to Brandeis University, a private research university in Waltham, Massachusetts, the word 'picnic' is offensive. It says: "The term picnic is often associated with lynchings of black people in the United States, during which white spectators were said to have watched while eating, referring to them as picnics or other terms involving racial slurs against Black people."  It recommends the use of the phrase 'outdoor eating,' instead.

'Rule of Thumb' is offensive because it is meant to be associated with an old English law that permitted a man to beat his wife, providing he used a stick no wider than a thumb.'

There are three issues. Firstly accuracy, let's make sure the above descriptions are accurate.