We don't have a free market.

In an actual free market, Walmart would behave totally differently, or else its executives would go to jail and it'd go bankrupt from the money it lost in lawsuits.

Capitalism is premised on the rule of law. The ideal free market includes law enforcement to prevent aggressive force, including: violence, threat of violence, fraud, false advertising, breach of contract, and property rights violations. Walmart, like approximately every mega corporation, does a lot of those things. And its executives do it intentionally, negligently and/or recklessly, so they're guilty of breaking the law.

I don't actually know what's going on with the "dead peasant insurance" – is Walmart profiting off that or losing money off it? In general, insurance is for risk mitigation, but Walmart has such a large workforce and so much money that it doesn't need to use insurance to mitigate the statistically predictable fact of some of its workers needing to be replaced (much more often because they quit rather than die). Insurance is normally for disasters, but a dead peasant isn't a disaster for Walmart. If Walmart is actually profiting off this insurance, that suggests the insurance company is losing money on this deal, which raises the question of why it's participating. But whatever is going on with this particular example, Walmart does plenty of other illegal stuff.

I know that many other Objectivists and "pro-capitalists" shill for big companies like Walmart. They should remember that our society doesn't have the capitalist system that Ayn Rand advocated and pay more attention to the many flagrant violations of the non-aggression principle by large companies.