Because there is a difference between the two.The double standard is the tendency to demand Discovery do better or not be Star Trek. To treat it like an exception in the otherwise infallible history of Trek.
And, no, I don't treat it the same as homoohobic or racist behavior.
With the other shows they at least meet a minimum standard of effort, Discovery doesn't.
When every episode matches up to Spock's Brain in the sheer number of logical inconsistencies you just gotta admit the show might have a problem.