"corporations are not people so when they do something that kills actual people no one is held accountable "
That _really_ depends on the jurisdiction.
New Zealand has laws which specifically hold individuals inside corporations accountable for unlawful decisions and has applied them (mostly in the area of unlawful anticompetitive activities) - usually with personal penalties of around 10% of the financial penalty the company is hit with, plus jailtime when things are serious - those penalties are applied to _BOTH_ the individuals making the decisions and their superiors - making CEO/CFOs far more cautious about potential illegal behaviour (especially corporate manslaughter)
It's important to note that "Limited liability" merely limits the overall financial liability of SHAREHOLDERS if the company goes bust. It in no way shape or form shields anyone from criminal charges - and the directors/board are front and centre if criminal/civil prosecutions are pushed forward as they are presumed to have signed off on policies.
The way companies seem to shrug off such stuff is more an indication of their legal abilities and the way that they've been able to shape decisions over the years than their actual liabilities.