FOR all men. Not TO all men.
You say that we should follow Jesus in our prayer and cite the Lord's Prayer and gratuitously ask what happened to "Do whatever he tells you."
So, I see NOTHING in the Lord's prayer about making prayers and supplications or giving thanks for all men. (This argument has nothing to do with the intercession of the saints. It has to do with how closely bound we are to the Lord's Prayer.) It would SEEM that Paul is asking for something NOT in the Lord's prayer.
Therefore it seems that Paul disagrees with you about the manner in which the Lord's Prayer serves as a model. The Lord's Prayer has no explicitly intercessory parts, yet Paul wants people to make intercessory prayers.
So I say "Evidently Paul didnt get the message...".
The question of "FOR" or "TO" is utterly irrelevant to the point being made. It is shucking and jiving, laying down smoke, changing the subject, ANYTHING but responding to the argument.
If the best your side can do is change the subject, then how strong are your arguments? Really.