I think you're half correct. While Apple certainly has every right to try to put mechanisms in place to prevent you from doing certain things on your device, t

I think you're half correct. While Apple certainly has every right to try to put mechanisms in place to prevent you from doing certain things on your device, the fact that you purchased it gives you the right to legally circumvent any of those protections to run whatever software you would like as long as the software is also legally obtained. That's why exempt from the DMCA rules are: "Computer programs that enable wireless telephone handsets to execute software applications, where circumvention is accomplished for the sole purpose of enabling interoperability of such applications, when they have been lawfully obtained, with computer programs on the telephone handset."