@Johan1311 First of all, reviews are blind. The guest cannot write a bad review in response to your review because the guest can't see your review, nor you see theirs, until the reviews are published. And once reviews are published, they can't be changed. So it sounds like you don't understand how reviews work.
Yes, some hosts have this fear of someone local seeking revenge for a bad review, but I've never heard of such a thing actually happening. Usually the worst that happens is that the guest responds to the host's review, denying everything the host had to say. Which isn't that big a deal- it's usually easy to understand who is telling the truth.
There are phrases that hosts sometimes use which most other hosts will understand, and the guest won't read as bad. For instance : "3 day stay". Not all hosts will understand, but most will realize you had nothing good to say about the guest but for some reason didn't want to be specific.
But as much as possible, you should try to be as honest and infomative, for the benefit of other hosts.
I can assure you that plenty of hosts, hopefully most, write honest reviews for bad guests- it isn't "impossible".
Aside from that, do you really think that Airbnb would change its policies because you asked them to?