My pastor is very much against the pre-trib rapture teaching.  His reason for this is he wants people to be prepared for what they will go through in the tribulation.  So it's like you say, he's warning people of the persecution to come, and the anti-christ, etc.   He definitely thinks pre-trib rapture believers will not be ready.  "Danger! Danger! You're about to go into the tribulation and face the antichrist!!" -- we surely hear that from him!

I have a strange theory about the whole debate.  The first part was brought to mind when praying about the truth of the situation.  It is the story in Judges 7 where Gideon's army must be reduced in size for God's glory.  If the Hebrew forces are small enough, then everyone will know that it was God who brought the victory.  So maybe this is the same situation for the end time war.  God must reduce the size of His army so all will know He won the victory.

The second is the centurion in Matthew 8: And Jesus said unto the centurion, “Go thy way, and as thou hast believed, so be it done unto thee.” And his servant was healed in that selfsame hour. 

This also was brought to mind during prayer.  Instead of lapping water to decide how the army is divided, it would be decided on the basis of how you have believed.  If you believe pre-trib, that's what would happen to you.  

The most recent that I was reminded of during prayer was No man knows the day or hour.  I got from that that this confusion, pre-trib, post-trib was intention.  God didn't want it to be known, because there wasn't one right answer.  Both are right.

But all this is just my speculation.