We have enough problems now with inappropriate dogs in public without encouraging even more by permitting ESAs. I'm not opposed to ESAs in public per se, but ONLY if they have been trained to behave properly and have suitable temperaments.
We know that 1 in four people in this country has a mental illness, and half of those have a dog. Do we really want to encounter 1 in 8 people dragging a pet around and claiming it as a service dog? I think not. That's why this is a bad precedent. All the dog does is provide emotional support. People already blow off service dog training as it is. Give them an even bigger loophole so that they think all they need is a nice doggy they love, and we're lost. At least with task training as the litmus there is some sort of assumption that the dog is trained. If a person can train tasks, the hope is that they can also train a dog to behave properly. Not always true, of course, but something is better than nothing.
If we had nationally standardized certification, then I'd be a-okay with public access ESAs. And I'd be a lot less nervous in general when encountering a vested dog in public.