Exactly, if you don't defend your trademark, you don't effectively have one. It's not enough to have a trademark registered. You have to actively go after people when they infringe. It's not optional. You can't be selective about it either. Oracle has not done that.

There are countless examples of people using the javascript name, incorporating it in books, articles, products, derivative works, etc. So, effectively the trademark has not been defended for decades. All fine with Oracle apparently. They never objected or sent any cease and desist letters. Oracle would not stand a chance in a court trying to enforce it now.