The original statement doesn’t use pejoratives. Viral is the best way that I can describe it, I suppose insidious is better, but that too could be considered a pejorative. I’m struggling to find a word because I view it negatively.
Self-preserving is the best. Thank you. I personally don't like self-propagating, when the truth is that it's free, but with a catch. Forcing people to do the right thing, even if the intent is good, is still forcing someone to do something the don't want to, or even can't.
I like the viral word personally, I see it positively as popular. Free software is pretty popular its so popular that even non free software is turned into "free beer" free software! ;) If its free and open source, free to use (legal or not) people will use it virally, like Windows was virally pirated because it was free, and linux is virally used in servers since they don't have to pay per core to Microsoft.