Use the search function on Prime with the term 'moisture in taillights' or 'condensation in tailights'. You will find that it is not an uncommon problem for the taillights. Less common for the center section.
Check to make sure that you are not getting moisture in the trunk which can be a sign of failed gaskets behind the taillights. I believe the center section has four little individual seals on the mounting studs. Failed gaskets can be a sign that the taillights might have been removed and reinstalled and it is not uncommon for people to reinstall the mounting screws too tightly leading to cracking of the mounting posts and another potential source for moisture to enter the housings.
Cars equipped with large taillight assemblies need to be vented to atmosphere. Where I live, it is entirely possible to go through an annual temperature change from -40 C to +40C. If the taillight assemblies were completely sealed, on those +40 C days (throw in some sun and the surface temperatures are probably 50C) the air in the taillight assembly is going to expand and push the socket assembly out, blow the seals or crack the housing. Venting the housing prevents this.
The taillight assemblies are vented along the bottom - I think just behind (not in) the red lens . The center section, being smaller, may be unvented (I have never removed to check); but, I expect it also has a similar vent(s). Probably does not matter now since your is definitely vented.
Aside from broken mounting posts allowing moisture to enter the housings, cars exposed to high temperatures can also experience failure of the seam between the red lens and the tailing housing along the top of the taillight. This will definitely allow more water to enter the housing. If your center housing suffers from this, there are multiple remedies that you can explore to fix this.
Even if the mounting posts are all intact and the seams between the lens and housing are in perfect condition, the fact that the housings are vented means you have the potential for moisture in the housings. If you wash the car on a day where exposure to the sun has increased the air temperature inside the taillights to 40 C (not too hard to do on a sunny day) the cold rinse water hitting the taillight lens is going to cause a rapid drop in the temperature of the air inside the housing. Sure as PV=nRT the temperature drop results in a pressure drop in the housing which potentially sucks in any little drips that may be along the bottom edge of the lens housing. Its grade 12 physics.
I have read about people baking their lens assemblies in the oven to remove the moisture and using hair dryers blowing air into the sockets (not an option for the center section). I personally would be inclined to purchase some desiccant, remove the lens assembly from the car and stick it in a sealed plastic bag with the desiccant for as long as it takes to dry out the assembly. While it is out, check the seam between the lens and housing to see if it has parted and look for damage on the mounting posts and try to avoid hitting the lens assembly with cold water when the temperature is high.
Full disclosure, I have yet to have a problem with taillight moisture on my NSX. However, my son had a recent encounter between a pintel on a large truck and the rear end of his RSX resulting in damage to the taillight and bumper cover. The body shop painted and replaced the bumper cover and replaced the taillight. After reassembly and paint curing they did a courtesy wash in a nice warm shop and then parked the car outside on a day where it happened to be about -35 C. Sure enough, rapid temperature drop and moisture on the inside of a brand new taillight. I think the design of the RSX taillights makes them really prone to this; but, if you explore I think you will find that it is a fairly common problem for cars with large tail light housings. As cars move to using LED lighting assemblies in housings with little or no air volume in them the need to vent the housing will go away and the moisture problem will disappear - to be replaced with some other problem?
