Of course it’s a bit of extra work and would violate the license and hence not something I would like to do to make an alteration I need for a project.
But for someone intent on stealing your work to profit from it it’s a lot easier that writing their own from scratch.

Consulting is nice, but selling software is more fun and profitable.

From our perspective we don’t like to sell our source because someone could just recompile it and turn around and sell it themselves or otherwise abuse our licensing.

The only reason for doing that what I can see is that you are worried about people not only using your source in their projects but instead using it to develop components that will compete with your own.
I’m not so sure if that’s really much of a valid concern, especially since it’s not to hard to decompile an swf to inspect the source anyway.

But it is quite a common attitude that protection of your intellectual property always takes precedence over convenience for the customer…even if that protection in practice is useless. Look for example at the hassle that the protection for Adobe products have caused their customers.
And the question is how much have it actually reduced piracy?
I sure didn’t by Flash because it’s hard to find a pirated version thanks to their protection system.