Is the peremptory challenge in jury selection now effectively meaningless?
Per definition in the Canadian Online Legal Dictionary a peremptory challenge is:
The right of the accused or the Crown to object to a member of the jury array being chosen to serve on the jury, without being required to offer any explanation for the objection. The Crown and the accused each have a limited number of peremptory challenges, which varies with the offence charged: see section 634 of the Criminal Code.
A few days back I stumbled across the article Federal Appeals Court Says Jurors Can’t Be Excluded Because They Are Gay which asserts a recent US court ruling saying that jurors can't be excluded for being homosexual. In the article it was also mentioned that jurors can't be excluded based on race and elsewhere you find that the same applies to gender. It seems to me that this basically means that, at least in the US, the peremptory challenge is effectively dead. i.e. a peremptory challenge is one where it's explicit that no reason is provided, yet they're reverse engineering the reason in such cases.
The BuzzFeed article linked actually contains an embedded copy of the appeal court's ruling. There on pages 3 and 4 you find both that the potential juror in question (a) had taken or was taking medicine from the companies under trial here over pricing of their HIV drugs and (b) had friends with HIV. Both would seem to provide an fairly plausible alternate explanation for why this specific juror might be one they'd want to bump.
(It is indeed the case that, to quote the head of the CDC back in November 2013 that "Unprotected anal intercourse is in a league of its own as far as risk is concerned" - and the CDC's got the data to show that HIV is vastly more likely to affect men who have sex with men. i.e. the man's answer to the questions above seem closely correlated with the question of whether or not he has sex with men. At what point though can you separate answers to questions like the two I mentioned above from someone's identity without making challenges in jury selection effectively meaningless?)