Sez who? The resurrection of Christ is celebrated across the board and across the world on Easter Sunday.
True, that the Melchizedek priesthood of Christ does not get the attention it deserves. But the fact that the New Covenant has superseded the Old Covenant does get plenty of notice. So do the other passages (at least on tis forum).
As to your use of the word "Christian sects" you are implying sectarianism. So where do you find this?
We don't seem to see that the resurrection is God lifting the law...
Throughout Pauls writings it is very clear that this is the case, yet rather than admit it Christians would rather reject Paul...
There are something like 40,000 sects of Christianity despite things like Ephesians 4:1-6 warning us against division as such...
It's surprising you take issue with the notion considering the violence that has happened historically between the sects that make it very clear we're not a united tradition at all...
Indeed, it is another proof that Christianity is going wrong...
Rather than be unified by the Spirit we argue over ignorant opinions.