"They are there to make profits to their shareholders so yes it's fair that they get a return on capital invested. Which they have done more than successfully in past years/decades. "
Yet they are not doing so today; their returns on capital don't even cover their cost of capital so your statement rings hollow.
"I don't get what your question has to do with taking advantage of lower operating costs to make record profits at a time of high inflation?"
Your premise of "lower operating costs" is totally false, and is not borne out by the facts.
Their cost base is not immune to the forces of inflation; their costs have gone up.
They are simply passing on those inflationary impacts to customers; just like every business does.
In fact, they are not even passing the full impact of the cost inflation to customers, but are absorbing some of them; the evidence of this is that their operating margins over the two years between 2021 and 2023 (the period when inflation accelerated) have gone down, and not increased (which is what would have happened if these companies were "gouging" customers:
[Information Source: Coles and Woolworths Annual Reports for 2021 and 2023]
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