You seem to think the day of Christ is "rapture day", but that doesn't make sense when you consider this was troubling news that rapture day is here.
It makes complete sense since Paul very clearly referred to "the day of Christ" (or "the day of the Lord") in the same context as Christ's coming and our being gathered to HIm (the rapture).
2 Thessalonians 2:1 Now we beseech you, brethren, by
the coming of our Lord Jesus Christ, and by our gathering together unto him, 2 That ye be not soon shaken in mind, or be troubled, neither by spirit, nor by word, nor by letter as from us, as that
the day of Christ is at hand. 3 Let no man deceive you by any means: for
that day shall not come, except there come a falling away first, and that man of sin be revealed, the son of perdition;
Apart from doctrinal bias, this passage is very simple to understand. In verse 1, Paul introduces the topic of "the coming of our Lord Jesus Christ, and...our gathering together unto him". An obvious reference to what we call the rapture, as Paul described in 1 Thessalonians 4:14-17. Then in verse 2, instead of him again referring to the day of "the coming of our Lord Jesus Christ, and...our gathering together unto him" he simply referred to it as "the day of Christ". That should be obvious apart from doctrinal bias. And then in verse 3 he refers to "that day", which again refers to the day of "the coming of our Lord Jesus Christ, and...our gathering together unto him" which he also called "the day of Christ". Paul did not introduce the topic of "the coming of our Lord Jesus Christ, and...our gathering together unto him" in verse 1 only to inexplicably change the topic in the very next verse. But, that's what you believe for no apparent reason.
No, the apostle was telling them to not be concerned about being gathered to Jesus, as though the day of Christ/day of the Lord is here, because that day, the day of Christ/day of the Lord won't come until these other things happen first. Not the gathering to our Lord, but the day of Christ/day of the Lord, a dark day of judgment and wrath. That's what was troubling to them. Telling them this day of wrath is here.
The day of Christ/day of the Lord is a dark day of judgment and wrath for unbelievers. Not believers. That's why Paul wrote this after describing what will happen to believers when Jesus comes in 1 Thess 4:14-17...
1 Thessalonians 5:2 For yourselves know perfectly that the day of the Lord so cometh as a thief in the night. 3 For when they shall say, Peace and safety; then sudden destruction cometh upon them, as travail upon a woman with child; and they shall not escape. 4 But ye, brethren, are not in darkness, that that day should overtake you as a thief.
So, we can see from verse 2 and 3 why the day of the Lord is called elsewhere a dark day of judgment and wrath. It will bring "sudden destruction" upon unbelievers from which "they shall not escape". But, then look at verse 4 above. Paul points out that day will not overtake believers as a thief like it will unbelievers. That is because believers will be changed to put on bodily immortality and caught up to meet the Lord in the air on that day rather than experiencing the "sudden destruction" that unbelievers will experience on that day.
A simple test is to ask you, the "Sheep / Goats Judgment" prophecy, will it be fulfilled exactly as written?
When Jesus returns. What are you testing exactly with this question?