TAANSTAAFL (There ain't no such thing as a free lunch), to quote Robert Heinlein. I for one was never under the impression that frequent flyer miles were 'free.' They are simply a rebate of some portion of a fee one is paying. Like it or not, as a customer if MCI (or anyone else) gives you miles or any other discount/rebate/reward, you will eventually pay for it in the form of higher prices--whether explicitly or implicitly.
I for one would prefer to have the cost itemized out as a tax rather than pay higher long distance rates (the other option), because then if I don't want the miles I myself recapture that money, rather than have MCI just pocket the difference. Thus, a user tax is actually quite fair in this respect. By having it itemized out I personally can calculate whether or not this cost is worth the benefit; if it is wrapped in to some other fee, this transparency is lost. That said, I will fault MCI for not disclosing what this line-item covers; they have had enough asterisks about the various Universal Service Fees, etc. that one more would hardly hurt!
I know we all like to think of FFB miles as 'free', but like it or not somewhere along the line we pay for them. Do you want to hazard a guess as to what ticket prices would do if all airlines collectively did away with loyalty programs (of course, none of us wants that, since the entire game is thatmost of us often fly on an expense account, in which someone else bears the direct cost and is usually less price-sensitive).
If you don't think the cost is worth the benefit, find a better package of services (as MileageAddict and others have done); that is what is wonderful about a market economy.
Apologies for the length of the message, and I too have complaints about MCI's customer service, but I also deal enough Russia at work that I have come to greatly value transparency and accountability--which is what MCI is in fact trying to promote with this practice.