It is interesting to note, that the word כשר (kosher) does not appear in the Torah per se. It appears in only one place in the Tanach, and surprisingly perhaps to many, it is in the book of Esther. That book itself was parenthetically one which was a matter of argument amongst the Rabbis in that some felt it should be included in the Canon whilst others did not. In the end, we know that the conclusion is that it was קדש holy, and Esther herself, as quoted, asked for it to be included by the Sanhedrin.
So, we have the single occurrence of the word in the story of Esther and Ahashverosh in her request to the latter that he consider her plea that Haman’s decree be annulled. In that context, she asked Ahashverosh whether her argument/plea was “kosher”.
It’s a striking observation because it centers around the concept of whether a plea/argument was (morally) proper = Kosher.
Today, and this is also certainly reflected by the Geonim, Rishonim and Acharonim, the use of the word Kosher is almost exclusively referred to food.
Perhaps we should revisit this term, especially in light of matters here and around the world, and apply the opposite word “Treyf” or “not Kosher” to matters of an amoral and/or Chillul Hashem causing, just as often?
I’m not sure about the rest of you, but I find it ironic? Kosher didn’t start from food but has somehow morphed to be only what we put in our mouths.