Yeah, you can trash all the gziped (gz compressed) files as root...or just let MacJanitor run the scripts that will perform the log rotation (amongst other things)...or run the scripts in the Terminal...or remove the .gz files in the Term. Just don't delete the current log files if you tinker manually and don't trash anything else.
Most of these files will be very small, but if not rotated they can consume a bit of space. My log folder is 36MB, nothing out of the ordinary and not a concern for HDD bloat.