Why is it then that regardless of their origin, words have been upgraded over time to reflect among other attributes cultural changes, and modernization but this word bestiality, which should be spelled according to the latest change, which is the English spelling "Beast," enjoys protection enabling it to remain unchanged despite the English upgrading? Is it another offensive effort to embrace political correctness?

The latest version is the version that should be used and that version is the English spelling, "Beastiality," regardless of who it offends or claims political incorrectness. IT is the most modern version; use it unashamedly.