it sounds wrong, on the account of I never had my "ability to buy groceries" taken away from me without proving my vaccination status, I've only ever seen it used for travel purposes.
both of those appear to be that businesses are allowed to refuse, not forced to refuse. In general, businesses are allowed to refuse business to whomever they want, where the law has exceptions for which things you aren't allowed to discriminate against: religion, race, sex, etc. At least this is how the law works in Canada, I am willing to bet Australia is very similar.
In germany there was a short time period during the pandemic where shops and some grocery stores denied entry without a prove of vaccination.
Here's a small headline form that time: https://www.bbc.com/news/live/uk-59501192
It was also widely discussed.
https://www.abc.net.au/news/2021-10-06/morrison-businesses-r...
https://www.news.com.au/world/coronavirus/australia/supermar...