Glancing through that article it appears the author is not questioning whether or not Bach composed the lute suites, but suggests that Bach composed the works for lute-harpsichord, not a lute. This theory has been around for a while, I am really not sure if its true to be honest. Either way, those works sound great on lute and guitar so this won't stop me from playing the works on a classical guitar. One of the nice things about Bach's music is it can usually be arranged nicely and retain a great sound on most instruments. I'm certainly not a staunch hip-purist, so just as many of the best musicians have performed his harpsichord works on a modern piano, I will continue to enjoy playing these works on a classical guitar.

 

My goodness, I would never suggest that we shouldn't play them on any instrument we choose!

 

Clive Titmuss? A pseudonym?