You missed the point entirely.
Subjecting yourself to death for what you BELIEVE to be true, is a common virtue.
Subjecting yourself to death for what you KNOW to be untrue, is extremely rare.
No, you missed his point. Dieing for something "proves" nothing, except the strength of the belief of the person willing to die. Since uncounted numbers of people have been willing to die for many, many mutually incompatible religious (and other) beliefs, their deaths "prove" nothing, either, except the strength of their convictions. No one claimed that non-believers died for something they pretended to believe in; that's a straw man argument. The argument is that dieing for what you believe in doesn't prove anything, anymore than the ability of a spoilt child to hold his breath, in a fit of tantrum, "proves" that he should get a cookie.
For many reasons, which I don't have the time to recite here. Suggest you go to one your local Veterans organizations and pose the question to them.
Is suicide virtuous?
No, unless you mean in the sense of someone doing an act of bravery which was "virtually suicidal".
Well, I beg to differ with you, but you did miss the point.
The argument is NOT that "dieing for what you believe in doesn't prove anything.".
The argument, rather, is...Nobody will choose to die for something that they do NOT believe in. And that is no strawman. There is ample historical evidence that those people witnessed events that they would not deny even as they were being tortured and killed.