The GPL is quite an open license. It only has one really major restriction, which is that open code and derivative works should stay open. "GPL-Infected" is a term used by people who, after grabbing boatloads of GPL code for free, wish to break that one restriction.
You might as well refer to proprietary code as "copyright infected" or even more insidiously, "patent infected". You're as likely to lose control of your code whatever license term you break, and at least the EFF seem to only be interested in the maintaining the GPL.
As opposed to, say, screwing you for everything you're worth.