Compatibility

[echosierra]

Not really, PCSX2 does not modify any copyrighted material. Whatever these hacks/patches do, I'm not sure if it's illegal or not but it definitely is NOT comparable to what PCSX2 is using/is doing.

Toxic DL for example, only patches an ISO image inside a disc. (img390.bin or something) fixes a problem when loading the dvd on pcsx2 (though some pirates use it too, that doesn't make the program a pirate program)

Patches such as that are legally questionable. There's no way to verify that they were created in a clean-room enviroment (ie no copyright-ed code or disassemblies are used), and for that reason alone shouldn't be distributed with the emulator or relied on in any fashion.
The emulator was developed without any Sony code and as such can be distributed freely, this can be seen by looking at the available source. Can you say the same for all the patches for various games floating around?

For example, consider a patch that alters some of the game models. If it's purely user-created stuff it's fine, but if the distributed patch contains any part of the original model it's illegal.

[Saiki]

I said nothing about distributing it either


edit: luis pointed out to me I should probably be more clear about it. Toxic DL stands for Dual Layer. it's a patch to fix the problem with reading the 2nd layer of a ps2 dvd