[To Sabbaton dia ton anthrohpon egeneto kai ouch ho anthrohpos dia to sabbaton]
'Dia' translated ''for' (man)" is nothing wrong with unless one took "for" as its only meaning.
"dia" has many meanings depending on whether the word that it precedes is genitive or accusative. In Mark 2:27 both "for man" and "for man" and "for the sabbath" are in the accusative, and that gives the word "dia" many different meanings.
Here are a couple of examples:
Mark 4:17 And have no root in themselves, and so endure but for a time: afterward, when affliction or persecution ariseth
for the word's sake, immediately they are offended.
Mark 6:17 For Herod himself had sent forth and laid hold upon John, and bound him in prison
for Herodias' sake, his brother Philip's wife: for he had married her.
Thus in Mark 2:27, the meaning could obviously be:
Mark 2:27 And he said unto them,
The sabbath was made
for man's (sake,) and not man for the sabbath:
--That is, for the sake of man, or for his enjoyment. Man was not made to be a slave to the sabbath as the Pharisees had made the sabbath. They were slaves to it.
The context in Mark 2 is very similar to the context in Genesis 3. Man in need! In need because of sin! Therefore God made the Sabbath to meet man in his need--in his need of redemption. Then 'dia' translates much truer with the sorrowfulness of that first of all Sabbaths when God made it "DUE to / BECAUSE of man", the SINNER. Of a Sabbath made for man's enjoyment one sees absolutely nothing in the Old Testament. The joyful Sabbath came through Christ's victory and is the NEW, and not, the Old Testament Sabbath. Sure, the OT Sabbath foretold the New Testament Sabbath. Read Exodus 15 the Song of Moses AND of the Lamb, the Song of God's Victory over the depths of the Red Sea grave, a Song of the LORD'S DAY his Holy Sabbath when He lifted Israel out of the depths and planted his People in the New Land.
This is just opinion and your own conjecture. Keeping the sabbath is a part of the law and the law cannot save. The law condemns. No man could keep the law except for Jesus. Salvation comes through Christ, not through the law. The law is a curse, for which Christ died.
Galatians 3:10 For
as many as are of the works of the law are under the curse: for it is written, Cursed is every one that continueth not in all things which are written in the book of the law to do them.
Galatians 3:13 Christ hath redeemed us from the curse of the law,
being made a curse for us: for it is written, Cursed is every one that hangeth on a tree:
But it was only symbolic of the redemption Jesus would bring the People of God wherefore a Sabbath Day's rest remained for them to observe --- the NEW Testament and RESURRECTION-DAY Sabbath of the Lord Jesus Christ; hence, "The Lord's (Jesus') Day".
The sabbath is Saturday, the day which is the sign of the covenant which God made between Himself and Israel and their generations forever. It does not typify redemption. It is part of that law which we cannot keep. It condemns.
NOW John was "in the Spirit on the Lord's Day" and although in exile JOYFULLY in the Spirit assembled together with all fellow believers in the New Covenant of Peace with God—God’s Covenant He from eternity had sworn by his Word, Jesus Christ our Lord and God of our salvation.
--It cannot be shown that Saturday is "the Lords Day," You have no evidence.
You really haven't considered all the context of the passage, have you?
Mark 2:24 And the Pharisees said unto him, Behold, why do they on the sabbath day that which is not lawful?
25 And he said unto them, Have ye never read what David did, when he had need, and was an hungred, he, and they that were with him?
26 How he went into the house of God in the days of Abiathar the high priest, and did eat the shewbread, which is not lawful to eat but for the priests, and gave also to them which were with him?
27 And he said unto them, The sabbath was made for man, and not man for the sabbath:
28 Therefore the Son of man is Lord also of the sabbath.
--Christ is Lord of the Sabbath as He is Lord of all things. David did as he needed to do on the Sabbath day whether it was considered work or not. The Sabbath is not made "for man," that is that man should be a slave to it, but rather for man's enjoyment or man's rest.