The alternative is to presume that all people with HIV pose a transmission risk which is simply counter to scientific fact.
There are many ways in which someone can limit the chances of HIV transmission to zero or close to it. Undetectable viral load is the most obvious way (and no, there is no likelihood of medication just stopping working with a sudden increase in viral load - that is the point of regular checks). Other ways include condom use or limiting sex to oral sex.
When you talk about non-disclosure in terms of, essentially, rape - you ignore a key legal component. The alleged rapist would need to know, or reasonably ought to know, that the alleged victim does not consent (or would not consent if they had all the information).
It’s not a justifiable imposition to conclude that the reasonable person would refuse consent solely on the basis of a persons HIV status if viral load is undetectable, or condoms are used, or a low-risk form of sex is engaged in. So it doesn’t meet the most basic legal criteria for criminalisation for lack of consent.