Rapeseed makes more than just oil–it's also a source of proteins

It's called canola oil in the US. I understand it needs to be highly processed since it naturally contains glucosinolates and erucic acid which are both toxic. In general it really isn't that good for you. Olive oil/avocado oil are better options if you have the budget.

Disclaimer: I am not a professional when it comes to food science, so defer to your own research.

Because adults can disambiguate words with multiple meanings and not get worked up about them.

Named long ago, when people weren't so sensitive about words.

  The term "rape" derives from the Latin word for turnip, rāpa or rāpum, cognate   
  with the Greek word ῥάφη, rhaphe.

https://en.wikipedia.org/wiki/Rapeseed

https://www.etymonline.com/word/rape (see noun, 2)