Something I keep seeing come up in discussions of Paladins is that fact that 5e did away with using a God with the Paladin. That is not actually true. The Players Handbook is a general guide for the game mechanics and NOT a guide to game lore within specific worlds. For the Forgotten Realms and 5e we can reference The Sword Coast Adventurers Guide.

This is directly from page 132 of that book.

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Most paladins in the Forgotten Realms, like clerics, are devoted to a particular deity. The most common paladin deities are those that embody action, decision, watchfulness, and wisdom. Torm and Tyr are both popular deities for paladins, as is Ilmater, who stresses self-sacrifice and the alleviation of suffering. Although less common, there are paladins of the following deities: Helm, Hoar, Lathander, Sune, Corellon Larethian, the Red Knight, Clangeddin Silverbeard, Arvoreen, and Mystra.

Their devotion to a higher ideal makes paladins popular folk heroes in the Realms. Many tales are woven about noble knights and oath-sworn champions, although pragmatists note that the tales often end with a tremendous sacrifice on the part of said champions.

The most common patrons of paladins of the Oath of Devotion and the Oath of the Crown (which is described below) are Helm, Torm, and Tyr—protection, courage, and justice—although Ilmater has his share of devoted champions. Those green knights sworn to the Oath of the Ancients might honor Arvoreen or Corellon, while avengers of the Oath of Vengeance follow patrons like Hoar, although there are also avengers of Helm and Tyr, meting out harsh justice.


Reading further we see the exception to the devotion to Deity appears to be the Oath of the Crown;

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The Oath of the Crown is sworn to the ideals of civilization. be it the spirit of a nation, fealty to a sovereign, or service to a deity of law and rulership. The paladins who swear this oath dedicate themselves to serving society and, in particular, the just laws that hold society together.

So when people bring up that the removal of the choice of Deity for a Paladin is because I of the game rules, I would point out that it's removal has in effect used game rules to break lore. In a GREAT RPG Lore is always king and supersedes rules require them to adjust to lore.