No you shouldn't be scared :). The first thing to note is that vast majority of companies will find running their tools or scripts on an Exchange or Windows box to be sufficient. The second thing to note is that if there is a need to manage from a non-Windows box, there are several options:
1) You can TS into an Exchange server (or a machine that has the tools installed on it) and run the scripts there
2) You can use several toolsets to manage the AD directly. This is not what we recommend to our customers as then you have to do your own checks and ensure a working system when you modify settings in the AD directly, however, LDAP is a fine protocol that is accessible from many tools such as Perl, Python etc.
3) You can run the windows version of the toolset (perl with Win32 extensions for example)
4) You can use SFU to run your tools on a Windows server box to get the best of both worlds.
5) You can write provisioning "front-ends" that live on a Exchange box but can be accessed through a web interface on a non-windows machine
The last solution is one that many partners adopt, and is one that is accessible on a wide variety of platforms.
Thanks, ~vivek