The GPLs are meant to be poison pills. That's what they are for. Mongo's use of the license this way is standard, then in addition they allow you to buy the antidote.
People giving out code for free is poisonous? Here is someone people saying: "Hey, wrote some nice software. Here. You want it? Take it. We like it. It's Free.".
Now if you want to take that software and give it to someone else, they ask you to not go around the hide where you got it, what changes you made to it, and not sue people for patents over that software.
Its a polite, if backed up statement, that people can't go around using other people software and then be exploitative about it. Play nice, or do not play at all. Is it really your view that doing so is poisonous?
