I've never understood how someone had the nerve to trademark "Bollinger bands", when all they are is just a measure of 2 standard deviations from a rolling mean

I've never understood how someone had the nerve to trademark "Bollinger bands", when all they are is just a measure of 2 standard deviations from a rolling mean of share price. It's like renaming 1+1=2 after yourself and and trademarking it's use.