That is the symlink target, not the ln target, which is exactly why the "target" nomenclature is confusing. Also note that not every "ln" has a "--help" or uses that help message as the output. For example, try on OS X `/bin/ln -h`.
Yes, it would be platform specific as the OSX ln command would not be the same program as the GNU coreutils ln program.
For GNU ln at least I don't find it confusing at all particularly considering the only other option is LINK_NAME. I guess YMMV though and it seems kinda pointless to argue whether it is or is not confusing. Perhaps a poll could quantify it.
I wasn't speaking specifically about GNU. Note though that even there you see a --target-directory, -t, -T flags that make literally no sense anymore once GNU reversed the meaning of the term.
