I'm curious that you said if people were really smart, they would stop giving money to Amazon, Wal-Mart, Microsoft, Google, etc., and then suggest that taking their stock without giving them money is bad. This seems contradictory to me. If stealing wouldn't hurt the company, then why would not giving money be a smart thing? If not giving them money is good, stealing would just increase those loses further and also be smart.

They all claim that they’re doing it to hurt corporations.

Personally, I think hurting dominant anti-social corporations like Walmart is a smart thing for society to do, but that's besides the point. There are plenty of far more accepted reasons to steal, such as preventing starvation (like stealing basic food from supermarkets). I assert that stealing essentials is more socially beneficial than allowing oneself and dependents to starve or die, and it's far more ethical to steal from multi-billion dollar income megacorporations than other households or smaller businesses (the alternatives). I would go as far as to say they are socially obliged to steal, because they are more useful to society alive than dead and the cost to achieve that is trivial to the theft victim.

They steal enough, the store is closed, many jobs lost.

Honestly, if we're talking about companies like Walmart, then I say good that the store is closed, those workers are now forced to enter (or even recreate!) jobs which benefit society rather than destroy other local businesses. This is clearly unfortunate to those who are temporarily unemployed as a result, that's real pain and it's valid, and it's unfortunate, but the store closure is still an overall positive.

How the fuck is that hurting the corporation?

Losing sales isn't profitable. Closing a store certainly isn't profitable. If theft didn't hurt the corporation, they wouldn't spend significant money stopping it.

Furthermore, for a publicly traded company, reputation damage is real financial damage. Reporting high theft and closing stores has a real reputational impact to investors.