You know that's just window dressing right? All companies participate in corporate philanthropy, but that's usually to build up the brand, not because they sincerely care about those in need. And besides, even if they don't appear heartless, it doesn't mean that the level of protection will be equal.
Let's face it - poorer neighbourhoods tend to have more crime. Poorer neighbourhoods are therefore more costly to police. Poorer neighbourhoods are less able to pay for private policing - and things in general, since they're well, poor. Do you see the profit logic here? Because it's obvious to me - if I'm the CEO, I'm only going to provide a standard of protection to those poorer neighbourhoods that they can afford, and spend more resources on rich neighbourhoods because that's what's profitable. That makes sense for the pursuit of profit, but does that make sense through the eyes of justice?
Don't get me wrong, I wouldn't want to appear as a heartless bastard. But all I would have to do is not "appear" like a heartless bastard - as long as I do that, I would do everything within my means to spend as little in those unprofitable neighbourhoods as possible. I don't know about you, but mere appearances is not acceptable.
You are incredibly optimistic about the ability for corporations to provide social benefits. You know that corporations screw up all the time even when they're already regulated? The BP oil spill in 2010 happened because of gross negligence even though they were regulated by the government. So why would you play with fire and give corporations to do what they want? Why should we need to have a mess to clean up before a corporation is regulated?
This is why government intervention in the economy is necessary, and why government intervention in general is necessary - because certain mistakes are intolerable and shouldn't even happen in the first place.