Google deciding not to distribute an application is not akin to making you into their slave. Pointing out that a warranty might be voided if you do certain things is not akin to making you into their slave. All your analogies to "walking off the plantation" do is highlight that you have absolutely no sense of perspective on this matter.
Several problems with your statement there...
1. Google didn't just "point out" that this application may void your warranty. It was already pointed out in large red, bold letters on the play store for the application so no further action on Google's part would be "pointing it out".
2. "Certain conditions" (whatever that means) ignores that in other conditions the application works just fine and has worked fine for thousands, even millions of users. If "certain conditions" was the deciding factor, then literally ALL the applications on the store could void your warranty in "certain conditions". Yet they aren't shutting down the store because of that fact.
3. Although the master / slave imagery is a bit strong you are still sacrificing the freedom to do what you want with the device that you own at Google's will. Google has made itself the gatekeeper by implementing that store and by seeing itself as the total arbiter of what is the best interest of their users.
4. Voiding of the warranty is only an issue where the warranty is in effect in the first place. Google is unilaterally deciding that ALL users, not just those covered by a warranty, should not be allowed access to this application. Although they own the store and have the right to do this, that doesn't make the decision correct.