My take on this is no they don’t. As long as they are truthful they only report on the quality of the product and prevent many people of spending a lot of money from losing it by buying something that doesn’t work.
If your product is shit your company does not deserve to be shielded from the backlash, this is the core of (classic) capitalism after all.
MKBHD is pretty popular. His subscribers are probably the demographic that might be interested in this thing. So I’m sure his bad review has impact. But unless he’s a big outlier or has a personal axe to grind with the company it does not seem like there’s any ethical consideration to making such a harshly negative review. People should probably be more suspicious of the reviewers who don’t give the product a harsh review.