@John8690
Yes, once both reviews are published, you cannot edit them. We can't see your review or the Host's, but based on what you mentioned above it was a balanced fair review and I see nothing wrong with mentioning the noise, although you could have said you are particularly sensitive to noise in the review. Did the Host leave you a good review?
Yes, Hosts prefer that guests notify them via message during the stay if they are having an issue so hosts can try to remedy that if possible. It is extremely frustrating for a guest to checkout having said nothing about any issues during the stay and then leave a bad review. Perhaps let the Host know during the stay if you had problems with the bed and perhaps they can help with that (buy a topper). That said, as you mention, not everyone likes the same firmness on beds and we have had 100s of guests rave about the bed, only to get one say it was "too soft".
The noise is is definitely relevant. Sometimes this is not an issue a Host can control and is a one-off situation (like a broken water main in the street that requires repair). However, if the listing is on a noisy street, or the Host is aware that ongoing nearby construction will continue for an extended period, that should be indicated on the Listing in several places. This includes in the property description and under Guest Safety Section under "Potential for Noise." That said, many guests don't read the listing properly before booking and it is disclosed, but the guest didn't see it. Are you sure the noise issue wasn't mentioned anywhere on the listing?
One thing to keep in mind is everyone's definition of "noise" is different and if other guests didn't mention noise in their reviews, then it's possible that it is just something you'll have to be sure of before booking in the future. Since your are such a light sleeper, I would send a message to the Host before booking and explain you are a light sleeper and very sensitive to noise and if the Host knows of any street noise, on-going construction, etc. in the area that could be a problem for you. Always send a message to the Host during the stay with any issues. Believe me, we want to know so we can address it if possible during the stay and not hear about it in a review after the stay. Most good Hosts will do whatever is in their power (and reasonable) to ensure a guest is comfortable.
Good idea to provide private feedback, both good or bad to a Host. This helps them correct any issues before the next guest arrives and if positive, helps them continue being a great Host. However, if your review was fair and balanced, then don't let a Host intimidate you. If you really feel the review was not appropriate, then you can ask Airbnb just to remove the review since neither Host nor guest can edit a review once both are published.