There is a thing called "negativity bias", where negative experiences have a greater effect than positive ones. So reading negative reviews is actually the natural thing to do.

Should I want to game the system. I would definitely post negative reviews on my competitor's products. Safety-related issues, like some component catching fire would be ideal but even a seemingly well thought out disappointed review could be effective. With that in mind, I am also suspicious of negative reviews.

I don't know if that happens in real life. It's risky, and attacking all your competitors is a lot more work than paying for glowing reviews for your own products, but it is not like discrediting your competitors is a new thing.