I thought the eveidence showed

1. Calvin concurred with the death sentence on Servetus.

2. He was familiar with Servetus' teaching.

3. He did not agree with the manner of execution but sought a less painful method.

4. He did not have the authority to procure arrest and punishment by execution. This was the action of the civil not church authorities in Geneva.

On a different point you will find plenty of bad fruit in the life of Wesley in the many disparaging comments and slurs he sent out to Calvinists. I suggest you take the time to read a biography on him.

As for judging whether people are saved by their fruits one must look at the whole tenor and character of their lives, not simply condemn them for one fault. Who of us could withstand such scrutiny?

As for whether we agree with the teaching of various Christian forebears we are to compare what they taught with Scripture which is the supreme (though not the only) authority in the church.

On a most serious note you state:

What is unChristian about disagreeing with the doctrine of the trinity as expressed by the Roman Catholic Church and Calvin, when NO ONE can explain the concept of the trinity to ANYONE'S satisfaction based ONLY on Scripture.

Even Dr. MacArthur has said he can't explain the trinity from Scripture, since it's a mystery, but he accepts the doctrine of the Church in faith.
There is a great difference between explaining the Trinity in the sense of fully comprehending it; and explaining the Trinity in the sense of showing what the Biblical data is concerning the Godhead. None of us fully comprehends the Trinity. All orthodox Christians accept the Scriptural truth of this doctrine and that it is faithfully reflected in the teachings of the church. Servetus did not accept these things and was justly condemned as a heretic.