I'm one of the person that gives 1* reviews. It says, simply, that I would not buy that again, and I'm sorry that I did in the first place. Not sure how that's vindictive, just honest.
On some platforms, you're giving stars for the seller, not the item. Try to be fair there, but there's a lot of vendors that have absolutely zero business in selling things--from horrible packaging to misrepresentation and so on. I think you could argue that's vindictive as well, and it quite arguably could be. And yet, it's the sort of review that I wish I saw before trying to purchase something from that vendor and having a horrible experience.
Fortunately the fake reviews are generally detectable if you've been researching a product for awhile.