How can it be said that Paul taught a pre-tribulational rapture of the Church given 2 Thessalonians chapter 2?

> 2 Thess 2:1-3: Now concerning the coming of our Lord Jesus Christ and our being gathered together to him, we ask you, brothers, **not to be quickly shaken in mind or alarmed**, either by a spirit or a spoken word, or a letter seeming to be from us, to the effect that the day of the Lord has come. Let no one deceive you in any way. **For that day will not come, unless the rebellion comes first, and the man of lawlessness is revealed, the son of destruction**. Paul appears to be saying that "that day" (the day of the Lord's coming and our being gathered to him) will not come unless two conditions (the rebellion and the revelation of the lawless one) come first. According to pre-tribulational rapture theory the rapture of the Church takes place well in advance of both of these conditions. If he is writing to reassure his pre-trib rapture followers that the Second Coming of Christ (Day of the Lord) hasn't happened yet, why has he listed two conditions that they will not be around to witness? Why not say, for instance, "The rapture comes first and you're still here aren't you?"