The more reviews I read, the more I think I shouldn't read any reviews. Like you say, even the best places get their share of horrible reviews.
However, with Airbnb (or VRBO or any other similar platform) I think it's important to read the poor reviews. Are they complaining about something frivolous ("it was hot and their was no AC" even though the listing clearly doesn't show AC or "it was noisy at night with the windows open" even though a quick Google search would tell you there was a bar downstairs).
Or was there a legitimate complaint that wasn't resolved by the owner. So, the refrigerator wasn't cold. Did the owner respond when you called and sent someone to fix it. Great! Did the owner ignore your calls or blame you for breaking it. Run!
How the owner responds while your there plus how the owner responds to a poor review will tell you a lot about the property.