I know how to respond to this: point by point!
1) In answer to the first charge, that Bach has no climaxes nor the capability to move the listener, I say: He who is not to be moved will not be moved! I defy you to deny that there is a climax in every phrase, as well as climactic sections in this piece, a transcription of one of the organ sonata slow movements:
In fugues, there are climaxes, and they are often done with a concentration and thickening of the texture (much as in modern music, somewhat ironically), but the way that phrases are structure is a little different because they must often remain open for longer periods of time to invite new voices in.
2) In answer to the second charge, that the public cannot hear multiple voices or will not appreciate fugues, I say: This is not an argument against Bach. This is an argument against playing a recital chock full of his fugues. What about the Chromatic Fantasy? Can the public not understand that? And, by the way, does this not contain the power to move the listener? What about the Italian concerto, with the desolation of its second movement and the exuberance of its third? With regard to polyphony, the public deals with it constantly in the symphonic repertoire; the fugue is simply the most intellectual of Bach's genres, though it often contains great emotional and expressive power!
3) In answer to the third charge, that we cannot compare Bach to Chopin or Rachmaninoff, I concede to you that we can't. And shouldn't! It is a different era, a different country, a different person, and a different means of expression. Apples and oranges, as the saying goes. That having been said, Bach likely exerted great influence on Chopin's later work as well as much of Rachmaninoff's writing.
4) In answer to the fourth charge, that an audience would choose Scriabin over Bach, I say: Why give them the choice? And how about the C Major prelude -- might they like that? We create the rules of the universe for the hour that we give a recital, and our audience accepts those rules. Perhaps we invite them in with something like WTC Bk 1's E Major prelude, or as I mentioned above, the C Major prelude, following with the fugue. Of course if you slam them with a fugue with no foreplay, they're less likely to like it! This of course goes back to my response to second question: Bach is not only fugues.
5) In answer to the fifth charge, that Bach is preparation for nothing, I say: What ignorance. Bach is the ultimate étude for the ear, and is at the same time pleasurable. In that sense, what he has done is much linked with Chopin. Bach is, as one pianist put it, "our daily bread," in that it keeps the ear in command of the fingers, and not vice versa. It builds our sense of rhythm, voicing (on many levels), balance, handling of textures, tone color (!), agility, ability to set character . . . am I forgetting anything?
6) In answer to the sixth and final charge, that we should not use dynamics because Bach had an instrument that was incapable of them, I say: Bach had other means of expression at his disposal, e.g., notes inégales and ornamentation. While it might show a lack of taste to use romantic dynamic contrasts, we should certainly dynamics to shape, as well as to delineate sections. Also, I highly doubt that he was imagining sound only in terms of harpsichord when he wrote the WTC (I keep returning to this work, since fugues seem to be Mr. Modern's chief understanding of Bach).
All best,
Mike