I’ve already referenced the practical: live performances are different to recordings.
A performance is a performance. I must have missed how you arrived at this distinction, I came late to this thread. But if you don't want to clarify it, that's probably better at this point.
Honestly, if orchestras started reassigning parts to different instruments we'd never hear the end of it. But for some reason when it comes to music for only 1 or 2 performers, people start acting as if the words at the front of the stave aren’t part of the score anymore.
Whatever the reason, the Bach cello suites have been performed in transcription often and over a long period of time. I don't make a habit of railing against reality. I simply choose to listen to these performances or ignore them - but I happen to enjoy some of them.
As to the other point, a “modern cello” is still a cello. The clue is in how people kept the name as the instrument developed. But more generally, the question of replacing obsolete instruments with modern ones (while interesting) is quite a different question to replacing a cello with a lute. Bach knew what a lute was.
Good. At least your philosophical argument does have limits.

I did stipulate, "taken to the extreme."