D&D 5E Paladin Code (3.X) vs Paladin Oaths (5e)

[Maxperson]

Then why should we expect them on Paladins?

Because they're not Clerics and take oaths that the Cleric does not. That said, I expect Clerics to uphold the tenets of their god as well and can face repercussions if they violate those tenets.