In many ways I agree with what you have to say. But I can see some arguments in favor of "Simple".

There seems to be a non-official standard usage of Simple, eg XML::Simple and Test::Simple. Simple has a specific meaning that a primary goal of the library is to be very easy to use.

A tool with a very specific function is easier to name than one that is generalized. Adding any specific qualifier or descrptive dilutes the generalized name. Sometimes Simple may be appropriate.

A very generalized tool that aims to solve the major problems in a given domain, while minimizing the learning curve probably should be called Foo::Simple.

Whether Simple was appropriate in my case is a moot point, since the name's already take. With the above in mind, I think I'll focus on how my library is different from other offerings and what the specific goals of the system are.

But, for now, I'm still drawing a blank.