Hatchback weatherstripping missing/needs replacing?

Just went through a carwash - not something I do often since I park in a very industrial area on weekdays & just not worth trying to keep the car clean. but it was getting out of hand.

When I opened my hatch afterwards, the rubber weather stripping along/under the right side of the rear windshield fell out. It's pretty worn. The same happened quite some time ago on the left side, and I never bothered replacing it. Do these need to be replaced? Will regular weatherstripping do the trick, or do I actually need to get a specific part?

And do you think this (the missing one) is maybe why my rear defrost stopped working (due to moisture getting in)? I haven't had it operational pretty much since I bought the car - it's actually possible it wasn't working when I bought it, but I didn't try to use it for several months after buying since I purchased car in the summertime (the weatherstripping piece came out after a car wash not long after purchase). One shop replaced the fuse for the defrost for me at one point, but that only lasted 3 days. The side mirror heat works just fine (I believe they're on the same fuse).