I think that at the time of the bible, dates were pretty arbitrary. If you were planting something, you did it x days after the last snow fall. Even in the middle ages dates were reckoned along the lines of “14 seasons after the death of King John.” Today’s preoccupation with dates and times would be incomprehensible to most biblical cultures. Yes, people who collected rents were calendar aware, but the priests kept the calendars and those politicians, whose time in office depended on the calendar, were known to bribe priests to extend their time in office.
The cosmic significance of, say, the 21st of May is non-existent. Time and dates are arbitrary. Look at how many times the calendar was changed for one reason or another. If God were going to do some serious smoting, why would he do it on a particular date? One would think that God would simply see the need and smote!
Nothing in the Bible is ‘arbitrary.’
The Bible is a masterpiece of exactitude and precision to those that take the time to study it fully.
Your statement is typical of those with zero knowledge of God’s word.