Why OSX symlink cannot Relative PATHs? System in OS X 10.11.4 El Capitan

$ cd $HOME
$ ls .
&gt; Dropbox
&gt; BTsync


Code which creates unsuccessful symlink

ln -s BTsync/ Dropbox/


Code which creates working symlink

ln -s /Users/masi/BTSync/ /Users/masi/Dropbox/


Evidence in size difference with files

$ cd $HOME
$ ln -s $HOME/BTsync/wfdb.zip $HOME/Dropbox/
$ ln -s BTsync/wfdb.zip Dropbox/wasi.zip
$ ls -la $HOME/Dropbox/
lrwxr-xr-x   1 masi  staff    41 May 17 22:45 wfdb.zip -&gt; BTsync/wfdb.zip
lrwxr-xr-x   1 masi  staff    46 May 17 22:45 wasi.zip -&gt; /Users/masi/Dropbox/wfdb.zip


Evidence with directories

$ ln -s /Users/masi/BTsync/cam\ local/ /Users/masi/Dropbox/
$ ln -s BTsync/cam\ local/ Dropbox/camLocal2
$ ls -la $HOME/Dropbox
lrwxr-xr-x   1 masi  staff    37 May 17 22:52 camlocal -&gt; /Users/masi/BTsync/cam local/
lrwxr-xr-x   1 masi  staff    25 May 17 22:53 camLocal2 -&gt; BTsync/cam local/


and visually same in Finder



which shows that the two commands are not the same in El Capitan.
Using absolute PATH only works.  

Evidence with Relative PATH

$ cd $HOME
$ ln -s ./BitTorrentSync/cam\ local/ ./Dropbox/camlocal3
$ ls -la Dropbox/ 
lrwxr-xr-x   1 masi  staff    27 May 17 22:58 camlocal3 -&gt; ./BTsync/cam local/


and a new screenshot





Why OSX Symlink cannot Relative PATHs?
This isn't about relative paths. Relative paths work fine.

If what you're trying to do here is create a symlink from Dropbox to BTsync, the problem is that Dropbox already exists. This means the symlink is created inside the Dropbox folder, named BTSync. Delete Dropbox and try again.

If you really meant to create a symlink inside the Dropbox folder, then both these commands work identically.