It isn't legal but USA has an interesting (as in the curse "may you live in interesting times") legal system where this is rampant and no one will ever be punished for it.

Companies use it to hide criticism (VW with emission, game developers with reviews, etc.) and YouTube is full of whining on their idiotic quasi-DMCA process where companies can claim and then take down or monetize content they don't own (Kevin MacLeod's royalty free music, public domain music, static noise, game reviews that conain gameplay and are negative, etc.) and you have to dispute it and provide your real life details to Google as if they are a court to make it go away.