Yes. It focuses on the least likely hypothesis because it’s sexier than plain old inorganic chemistry.
Yeah, extraordinary blah blah... we all know the quote.
That being said, the paper hasn't been rushed, the live presentation was very balanced, phosphine was considered as a biomarker before (which is why it triggered the proposal) and a credible attempt was made to review all the known/potential pathways.
That being said, old inorganic chemistry in unusual physical conditions will probably give us the answer at some point I guess.
I am severly biased, I confess. I want that question of life elsewhere to be answered conclusively before I die. But I'd prefer being nuked by pretty sexy Cylons to to dying of some kind Andromeda Strain induced disease.