Tasha, we need to be careful here and make sure we're not spreading (no pun intended) deficient information. As is often the case, you're using the word "herpes" as if it's a one-size-fits-all word that indicates an STI. This has been an ongoing issue in society due to a lack of education on the subject of herpes and STIs in general. So often the word "herpes" is meant to indicate "genital herpes". While it is true that genital herpes is categorized as an STD, oral herpes is not. Oral herpes is commonly transmitted from oral-to-oral contact (i.e., kissing) and is mostly transmitted via HSV-1. While HSV-1 can be transmitted through oral to genital contact, it's rare. Genital herpes is usually transmitted via HSV-2 (and can vary rarely cause oral herpes). Without knowing the details, I'm willing to bet the case(s) you were involved with involve HSV-2
The problem is, as is the case in much of biology (as we've seen take place with COVID-19), biological organisms don't fit nicely into criminal and civil law. Needless to say, there are clear cases where STDs are transmitted and legitimate cases can be made where a defendant violates various Health and Safety Codes. This is often true of genital herpes, and several cases have been found in favor of plaintiffs accusing defendants of knowingly or unknowingly transmitting genital herpes. However, transmitting oral herpes is not transmitting an STD (by CDC definition). I only know of one case (in California) where HSV-1 (common cause of oral herpes) was involved to make a civil case against a defendant. The defendant knowingly had HSV-1 and transmitted it via oral to genital contact, causing the plaintiff to contract genital herpes (now an STD). While this is a rare transmission, it can happen. Though there has never been a successful case in The US made—citing Health and Safety laws—from oral-to-oral herpes transmission, that I know of. Though I welcome any information anyone has there.
I think the issue here is just how easily HSV-1 can be transmitted orally. It would be very difficult to prove someone contracted oral herpes from someone unless they could prove they were HSV-1 free up until a certain point, and from that point on the person never came into any kind of oral contact with another personal other than the defendant. And oral contact could simply be sharing a bottle of water. Yes, a case can always be made, but cases "can be made" concerning anything and are only as strong as the actual case being made seems to a judge and/or jury.
On a personal note, however, I'm worried that the case above, involving HSV-1, sets a bleak precedent. Until the stigma of herpes is removed, if cases involving transmission of known HSV-1 become more common, this might lead to less and less people getting tested, which is a negative thing. While one lesson in the above case is to, yes, disclose any HSV diagnosis before performing oral sex, many will also take the "lesson" to mean: don't get tested for STDs. In fact, many doctors don't test for HSV-1 or 2 with routine STD panels because both are very common. Many people with either don't even know they have it until tested. This is especially true with HSV-1 where it's thought that anywhere from 50-90% of the population is carrying the virus. While I don't advocate this line, it's almost like saying: you likely already have HSV-1, so don't bother getting tested because what you know can hurt you.