Think about it from your own perspective. Would you want it to be legal for your sexual partner to hide the fact that they’re HIV positive from you? No person has the right to knowingly put others in jeopardy or endanger their health.
Democrats like Buttigieg argue, though, that due to advances in medical technology and HIV treatment, it’s possible for someone to have HIV but not be contagious. This is true, in some cases, and it’s a wonderful advancement. But it still doesn’t justify the repeal of disclosure laws — not even close. For one, having an “undetectable” viral load, and therefore not being contagious, isn’t a permanent status. It can fluctuate. So while yes, tests might show that an HIV-positive person is not contagious at one moment, that can always change, leaving enough risk that to warrant mandatory disclosure.
I, for one, would sure as hell want to know if a sexual partner has HIV, whether they think they’re contagious or not. And if they’re really undetectable and therefore not dangerous, then there’s little harm in having them explain that to a sexual partner.