For "Fred" to be pained, because "Joe" sees fit to "break-in" a firearm, is silly. Fred didn't spend any money on it, lost time over it, waste ammo doing it, or anything along those lines. If Fred gets pained, it's because Fred has an issue with someone doing something that Fred doesn't support. Many products end up performing better when they're broken in..... motor vehicles, shoes, guns, mower engines, hell... even floor mops have break-in suggestions....
New York City Industries for the Blind - Mops
I have never experienced any issues because I didn't break in a gun,
but I have broken in many very expensive barrels, and experienced excellent performance afterward.
I have several Kreiger Barrels, and I adhere to their suggestions. Kreiger recommends break-in as much for future cleaning, as for performance.
Break-In & Cleaning
Some may need to consider 200 mg of Ibuprofin 3X a day for two days for pain. Apologies. :smt1099