When I unzip the mod in my mods folder the resulting directory is world writable. Meaning any user on my computer can just edit files, delete files or store their porn there. No other mod I used has those permissions on their directory.

Please check if your source directory is world writable or if your zip tool has some options to change the permissions.

As far as I know, extracting zip archive on Windows restores no permissions from the archive. Windows resets them to match inheritance from the parent container.
On *nix systems restoring permissions from zip archive can be done, but neither unzip, nor 7z do this by default.

How did you manage to do this? :D

for i in *.zip; do unzip $i; mv $i zips/; done

And the mods folder is not world writable:

drwxr-xr-x 79 mrvn mrvn 86 Nov 7 18:25 mods