Sometimes these days it feels like people forget cold exists. They catch a cold, get mild symptoms, and their first thought isn't "oh, I'm glad it was just a cold and I quickly recovered" but "wow, good thing I got vaccinated, these covid symptoms were really mild".
Ok, I expected some kind of treatment. We do need the same certificate in sweden too, but only from the 5th sick day or so and I think they give certificates for regular cold over the phone.
That is not a legal requirement, no. (not just for AUs, but a bunch of other things too it has been waived, again so that people don't need to go visit their doctors in person during the pandemic if it can be avoided. You can call a doctor you never went to for a sick note or a video consultation)
There has been an exemption to this rule for a while now. If your doctor doesn't do it, find one who does.
As for hanging around in a waiting room, I agree it's insane on many levels. I usually ask very directly if it's okay to come back in a while instead of waiting around. Though my primary health care provider has people with a cold wait outside in their garden, which is much better if you come prepared.