It isn't. It's an example of ridiculous things that have been done in Star Trek before but are accepted as part of the inherent weirdness of Trek. And, not to be too technical, your own post contradicts your point. Your response to Greg Cox is that Star Trek is space opera, not hard SF, but then flip around on me and state that the spore drive has no place (and neither does Q) in a hard SF setting.This is absolutely "whataboutism" - trying to distract from the current topic by pointing to other, non-comparable things and ask "what about them?"
So, you'll forgive me if I'm not confused as to what standard is being applied and why it is hard to take such criticism seriously. The arguments come across as inconsistent as to what level of magic is acceptable in Star Trek. That's frustrating and confusing and comes across as "New Trek can't do anything right."
Agree to disagree. If I can accept the weirdness of the Traveller or Q then the spore drive weirdness is, to me, just as acceptable.The mushroom drive is the main plot element of DIS, as such it deserves more focus than a one-off line from the Traveller or Q. That's why it's annoying if it becomes visible even less thought went into that.