Like when the creator does their spiel for whatever sponsor.
If they make a bad product do you want more of it, even for free?
Like, reviewers get to the point where companies send them free product for review from a long period of legitimate reviews that get them a large enough audience. It’s unlikely they’re getting their main profits from free products sent.
Obviously you shouldn’t take a single person’s review as gospel anyway, but just them getting a review copy of a thing isn’t a sole reason to discredit their opinion.