Even though you're right, sometimes, businesses do evil things like creating a negative image for the competitors to stay ahead of them in the business, but I think reputable businesses/platforms don't do such things but they focus on improving their own platform and services so that the competitors can't get near them, and that's how it should be.
If your business is already too good, you don't need to try and bring down other businesses only to shine.
In the business world anything can happen.
Let's not go too much further so we don't dirvert the conversation here.
Having reviews are good but there is a chance that some of them will be like not honest while some others will be negative. There are patterns to look out for to know the genuine ones. But having a place like this and other platforms where they are present will be the best to request instant feedback.