Not really, if you read the article in full.

In our analysis, only three per cent of the over 200 explanations for food price changes point to grocer actions or other agency in the private sector as driving price increases. This reflects a tendency to portray food prices as erratic and overwhelmingly opaque.

Other issues — such as the over-reliance on fossil fuels across the supply chain — also go unmentioned.

It's really shitty wording, but they're basically saying "of the 200 proposed causes, only 3% of those proposed are about grocer decisions" rather than "grocer decisions make up 3% of the cause in rising costs".

In the rest of the article announcing the report (it isn't released yet), they pretty clearly call out anticompetitive behaviors and price fixing:

These reports also rarely consider the decisions that grocers and other private sector entities have on food prices. Increased consolidation and concentration in the grocery sector is a structural issue that deserves scrutiny.

The bread price-fixing scandal a few years ago showed how a lack of competition enables price manipulation and hurts consumers. Canada’s Competition Bureau recently announced they are launching an investigation into the owners of Loblaws and Sobeys for alleged anti-competitive conduct.

In the United States, there is also strong evidence that the private sector has been profiteering on supply chain issues and inflation. The U.S. Federal Trade Commission likewise recently found that big grocers used the pandemic as a smokescreen to pad their profits at the public’s expense.

The underlying thesis of the article is basically "people keep asking why food is expensive but all these reports are unscientific and all but 3% of them neglect things like price fixing and monopolies".

What we need is a new approach. Food is a human right, but a unique one in that we rely on the private sector to provision it. We should expect a higher standard than with other consumer goods, and the private sector has arguably not earned the benefit of the doubt given their history of price fixing.

One positive step towards generating trustworthy evidence about food prices would be to incorporate transparency measures into the code of conduct the Canadian government is developing with grocers. This could include third-party audits, open data-sharing and a clear breakdown of what’s driving price changes — from the farm to the shelf.

The article authors (and report authors) are very based.