Providing uninstall is definitely a good idea. I won't deny it, but how do we
know where we have installed from our previous install? We can scan some common
paths, but that doesn't guarantee all the locations where the libraries may be
installed. I am sorry for strong words here, but I am suffering from this
problem. It is actually not possible to look at all the *stupid* paths that our
distributions would put these libraries in. It turns out to be extremely
distribution specific, which may be hard to search for during uninstall, because
you are most likely to run make uninstall from a new package with which you did
not install. 

 * Scan ~/lib/python by default, just as many other paths are scanned by default.
 * Is it worth scanning ../lib/python?
These 2 cases work only if you are sure of running make install-home last time,
which was clearly not the case for you, since you had not done install-home but
just install. Also in the environment I tested, I first installed my distro's
binary from the repo and then did install-home for 1.2 tar.gz package.

So considering all the above difficulties, I personally feel, a good idea for
now is to just clearly point out in the documentation(i.e README file and online
resource) to make sure to remove all the previous install libraries from where
ever we installed or install in the same method we did last time as many other
Python based projects do for now. 

Just my personal opinion. Will leave it for other contributors and developers
who definitely know about this better than me.