You are certainly entitled to your opinion. To tell you the truth, I have not noticed the "frivolous" examples you mentioned, but feel that Wildmon has been judicious in his use of the influence and monies entrusted to him as a minister of the Gospel of Jesus Christ and a proponent of social preservation (society reflecting, to some reasonable extent, a Judeo-Christian ethic).
On the issue of preaching the gospel on the streets, I have a friend who was denied a permit (required to use certain public venues) to preach in San Francisco, though these permits are routinely given to a plethora of "immorality promoting" groups. They went to court, represented by the Rutherford Institute, and were still denied the permit. This ministry has had an ongoing presence in San Francisco for over 20 years, and is well known and respected in the Christian community.
There is a hostility toward Christianity that is increasingly evidenced by our public institutions and government officials, and the fact that the church has largely abandoned the streets and public square has led to an increasing willingness on the part of public officials to try and confine the message of the gospel of Jesus Christ to the church building.
If we don't use it, we will lose it!
The video portions I saw of Marcavage and his fellow DEFENDANTS were no different from some of the ministries I have personally engaged in. I do not see how they in any way violated their Constitutional right to free speech.
What happened to your friend is a shame. I love "street preachers"- I am a Christian, and nothing can brighten a day more for me than being approached by a fellow Christian to talk about our beliefs and share what the Lord has done for us.