The problem is that Amazon often doesn't seem to really investigate issues in any depth at all; they just kick the seller off reflexively. It's trivially easy to be kicked off the platform for reasons other than doing something legitimately "bad," such as software error, human error, or even a deliberately orchestrated fraud campaign conducted by your competitor -- and many other sellers don't get kicked off for doing the same thing, or worse. It's all very random.
Transparency has nothing to do with it.
Amazon has a history of shutting down Fulfillment By Amazon seller accounts in an extremely arbitrary and capricious manner.
If they only shut them down due to legitimate complaints then sure, you might have a point. The story I linked proved that's not the case, and there are many more like it. That man's life would still be in ruins if he hadn't (luckily) gotten so much attention through Reddit and HN.
That's really only on the West Coast. People don't live or die by Yelp here on the East Coast. Frankly, I'm always surprised to see people are still using it after all the revelations of extortionist behavior they were engaging in against restaurants.
Yes, because people are poor at dealing with selection bias. A data source with 100% real and true complaints and favorable reviews can tell any story you want it to with the right filtering, so especially in the presence of a malicious adversary you have to completely discard this data from your decision making.
That's a false premise, which assumes any and all complaints are made in good faith. Some people are assholes and will leave a bad review because they disliked the person who delivered a meal or any number of other spurious reasons. You really sound like the sort of person who has never worked in any other field than IT and has a naive and largely illusory view of business conditions.
EDIT: Oh, and speaking of Amazon, Google and their automated bans, my SO's company's work account got temporarily blocked by Google recently, apparently for the sin of sending several files in quick succession to her boss' account. Apparently "atypical usage" is grounds for a ban now. Fortunately, the account was unlocked few hours later, and I didn't have to make fuss about it here on HN...
This is a valuable service to the consumer and good restaurants will thrive while bad ones will fail.
Also, any halfway decent owner/marketer knows you need to capture email addresses for people you want to sell to. Never rely on social media alone. Just use it to get them to give you an email.