This is a fascinating discussion, and I doubt I will add much insight beyond the great points previously made, but I had an interesting conversation on this topic today.
I am a Protestant Christian, but not fanatical about it. My son has split time in HS between private Catholic HS and Public HS. Today, I had lunch with a good friend and fellow baseball enthusiast who is Jewish, but not fanatical about it. He has 2 boys who are launched in life, and who went through their years of HS and Collegiate sports.
I told him about this thread, and the issue raised in the original post, and asked his take on it. Immediately, we arrived at the same conclusion many of you have reached: the Coach-led "optional" Bible study is inappropriate, because of the issue of the position of authority and power the Coach holds over the players.
Yes, the religious aspect of it compounds the sensitivity; but the primary problem is that it is an inappropriate activity due to the authority the Coach has over the players.
We say it all the time that the definition of "optional" workouts, field days, fund raising, etc. means that "if you opt to skip them, you have opted not to play for the team."
How can a teenage kid be expected to see any "optional" activity being led by his Coach in any other way than these other "optional" activities?
Take religion out of the mix. What if the Coach was conducting "optional" Amway meetings and invited the kids to consider starting their own part-time business? What if the Coach organized "optional" volunteer days for local charities or community organizations? Would your players feel a subtle pressure to participate, and would you as a parent feel a pressure for your player to participate?
The rub here is that these players are a captive audience -- they cannot quit the school and go join another team -- and the Coach has authority over them. The religious aspect just compounds the problem, by a coach stepping out beyond the bounds of his scope of work.
In the work place, who does not buy Girl Scout Cookies from the Boss' kid? There, you are an adult of equal standing, who has the power to choose to leave your position to play for another team.
My friend was more firm on the need to confront the matter than I, and that did have to do with the religious aspect of the over-step by the Coach. Truth be told, if roles were reversed, I would be the one who would feel the stronger need to confront the issue.
When we chose to enroll our son in a private Catholic HS, we knew he would be required to take religion classes -- rooted in the Catholic faith. We made that choice going in. We (and the school) told him to approach these courses as he would any ethics & morals or history course. Listen, learn, be respectful, and learn the answers to pass the tests. Whenever he wanted to discuss differences between what he has learned at home, in church, and in school, we discussed it at home.
His biggest issue was that the new Head coach forgot to lead the team in prayer before the first game of the season ... and they won. they proceeded to pray for the next few games ... and they lost. Like any good baseball player, he asked the Coach if they could stop praying because it was bad luck.
What to do? If it bothers you, then my friend an I suggest respectfully confronting the Coach on the grounds of this being an inappropriate activity because of his position of authority over the players. You can discuss the religious sensitivity, but make sure that you keep your eye on the ball -- it is about an inappropriate role for the Coach. There is no need to turn this into a religious war ... and I expect that a Coach of good heart and motives will see this if the issue is couched appropriately.
As I said, I probably did not add much to the dialogue, but it sure made for a fun lunch discussion.