The crimes of capitalism are tough to quantify, and i'll explain that in a minute. But let's say for the sake of argument that we're talking about things like reckless disregard for the environment which could include poisoning the air, drinking water, creating conditions which can contribute or lead to people's homes being destroyed, or losing their lives. It could also include mis-treatment of labor, via unsafe working conditions.. or collusion to suppress wages and other things of the like. If i'm missing anything then please let me know.
All of these are driven by greed, according to anti-capitalists. If it wasn't for capitalism then these rich assholes wouldn't have a reason to engage in nefarious business practices. It's that profit that's driving them to cut corners, screw workers and such so they can make some extra money for themselves. That's a fair criticism as cutting costs does mean higher profit for those who own/run the company. The system itself didn't compel them to poison the drinking water but it certainly didn't discourage it.
But, let's say that the company's consumers knew that they were doing that? Would they continue to purchase the product/service from that company? Quite likely, no, so long as an alternative exists or can be created. These corporations or people with a lot of money don't inherently have any more rights than anyone else, and they're subject to public opinion and laws as well. A combination of visibility by consumers and a corruption-resistant law enforcement arm can mitigate the impact by these types because they don't inherently hold any rights that other people don't. Capitalism doesn't automatically imbibe someone with rights under the law that someone else doesn't have.
Conversely, socialism or communism doesn't respect someone's right to realize the fruits of their own labor. It says that whatever you earn is put into a pot to be re-distributed to everyone equally. It's what nuclear families do really: mom and/or dad work to support everyone, and kids realize the fruits of mom and/or dad's labor without actually doing the work themselves, and that's great.
But who makes the decision on how things are to be re-distributed, and who actually carries that out? Who collects everything in their big bag of money and who actually tosses out dollar bills? By virtue of saying that everyone owns that wealth, you've inherently said that everyone is entitled to it, but that wealth has to go through some process by which is gets re-distributed, and therefore someone has to do that. It would be the same for anything: money, health care, education, etc. Any good or service that has been deemed to be "socialized" needs some aggregation and distribution mechanism to it, and that falls on some authority delegated by the collective. This is called "government." Naturally, when all of something is first aggregated through one central source before it's distributed out, that aggregating authority is in control of a WHOLE lot of wealth/power.
So, socialism doesn't itself compel government to become corrupt but it certainly sets the table just perfectly for it by funneling all that given wealth through government. All it takes is one or a small group of assholes to suddenly go "yea, all that money you just earned... it's mine/ours now and you'll take what i give you or else." When that happens, the people have two choices: accept it or speak up as dissidents. Dissidents are troublesome for a system predicated on everyone pulling on the same end of the rope, so they become inherently dispensable because we've already established that they share equally in the benefits that the system provides even if they don't contribute to it.
Looking at the fact that both systems are comprised of flawed humans, the negative view of both systems would consist of the following:
1. The system encourages distributed instances of malice and malfeasance varying in size and scope of people impacted when certain groups of people (corporations) get quite large by virtue of having wealth/product/service held by individual parties unequally.
2. The system encourages a single instance of malice and malfeasance that impacts everyone equally and totally by virtue of having all wealth/product/service held by one single authority charged with distributing said wealth/product/service.
