Isn't the essence of emulation to use games you (most likely) don't own? Aren't game emulators condoning game piracy?
No, the essence of emulation is to run software in environments that are not or no longer supported. Consider the case of DOSBox:
DOSBox is a DOS-emulator that uses the SDL-library which makes DOSBox very easy to port to different platforms. DOSBox has already been ported to many different platforms, such as Windows, BeOS, Linux, MacOS X...
I could keep around that 486SX with MS-DOS for running an old game, sure (double speed CD-ROM reader, FTW!). But a decent emulator saves me that trouble.
Local consumer protection laws may allow people to make private copies of software they have purchased or licensed, or may allow them to reverse engineer parts to make it run in new or uncommon environments, even if expressly forbidden by their license.
The use of an emulator, or trouble in using such an emulator, is not evidence of piracy. That's not to say that there are no shady individuals using emulators to facilitate piracy—that'd just be naïve—but we shouldn't automatically presume guilt based on this. Judge case by case.