It's just simple courtesy.
Someone rationally deciding that they're comfortable with a low probability risk is different from me knowing that my presence would change those probabilities significantly.
Discussion
Dude huge bummer. Hard to do, but try to think back to before covid. Do you feel crappy enough you'd isolate pre 2020? If yes, don't come. If no, come. In either case, stop testing!
I coach high school gymnasts and we tell them: "If you're sick (cold, flu, whatever), don't come to practice." Typical macho culture is to idealize Michael Jordan playing in the Finals(?) about to pass out from the flu.
But as coaches, we don't want half our team going down because Bob was so "brave" to come to practice when he was sick. In fact, Bob would be a shitty teammate if he showed up and ended up weakening our team. We care more about pragmatism than old-school notions of dedication at all cost.
And there's no guarantee that something that's mild for me would be the same for someone else. I sat next to a ~75yr old man at lunch today. Had I known at the time, I wouldn't have just sat there and thought, "pfft, I feel fine so I'm sure he'll be fine."
I'm just suggesting the pre covid era conventions on the topic of flu and similar illnesses were already sufficiently cautious. The new model of testing a sore throat or runny nose and quarantining like its tuberculosis has tradeoffs that are seldom discussed. I view them as not worth the damage they seem to cause, vs the pre covid approach of using symptom severity, not a test, to determine the "responsible" approach.
I get what you're saying, but at least attend to the perspective I just shared above.