Sure it's grandstanding, but is it even Constitutional?

Obviously, having nothing else to do, Congress has decided to hold hearings on steroid use in Major League Baseball. Several things about this jump out to me.
First, unless prescribed by a doctor for a legitimate physical problem, any steroid use would have been illegal. Unless granted immunity the players in question would be idiots to confirm in a public forum that they used illegal drugs. Their lawyers surely will advice them to invoke the Fifth Ammendment and refuse to incriminate themselves.
Second, the name of the committee,the House Government Reform Committee, leaves me wondering how this issue is any of their business. Is cleaning up druggies in baseball part of "Government Reform?"
Third, I re-read my copy of the United States Constitution and no where in that great document does it even say that Congress has any subpoena powers. Congress issued a report titled "Congressional Investigations: Subpoenas and Contempt Power" in 2003. That report acknowledges no article of Constitution authorizes the use of subpoena power but go on to claim that the authority arises from past precedent. To me, that means the power is derived from the fact that their predecessors got away with it.

My real beef with the whole charade is the waste of money involved. We have a budget of over two trillion dollars and you don't get to a trillion without a lot of minor waste. No one ever accounts for the money wasted holding hearings and then printing results. How much money does our government waste accomplishing nothing? If asked about it, I'm certain they would say it is a relatively insignificant amount. True, if you're used to wasting millions then wasting hundreds of thousands will seem insignificant. However, regardless of the amount waste is waste.