Actually, it's not a critical failure. Season 1 is 82 % on Rotten Tomatoes. However, it is a failure among some vocal members of the Star Trek fandom. But what Star Trek show wouldn't have haters? Every fan who's a critic of Discovery has their own idea of what their perfect Star Trek series would be and if that series were ever to be produced, an equal number of haters would appear for it as well. Every single Star Trek series after TOS has had a lot of haters in the fandom, and the trend will continue forever.
Agreed. I agree that Discovery had quite a few plot issues, but love it so far in spite of those. In the same way I love most things Trek in spite of their flaws, and they all have them. Probably TOS more than any due to time in which it was made. I would also bet large sums of money (if I had it) that a greater proportion of everyone who hated Discovery are shouting about it here, or Reddit, than lovers of the show are popping in to sing its praises. That's the just way the internet tends to work.