Based on the answers from this question Is a +1 chain shirt strictly inferior to a breastplate? Does +1 armor give resistance to damage?
DMG pg. 141
Most magic items are objects of extraordinary craftsmanship. Thanks to a combination of careful crafting and magical reinforcement, a magic item is at least as durable as a nonmagical item of its kind. Most magic items, other than potions and scrolls, have resistance to all damage. Artifacts are practically indestructible, requiring extraordinary measures to destroy.
It doesn't seem right that magic armor in general would give damage resistance when there is a specific type of armor that grants resistance to one damage type called Armor of Resistance (DMG pg. 152).
It seems like the quote on magic item resistance is for the item itself and not to the weilder or wearer of the item. Does magic armor grant resistance?
Best Answer
The armor itself has resistance to damage, it does not confer this to the wearer
As you've quoted, the magic item itself has resistance to damage, but there is nothing that states it gives whomever wears it resistance. Because it doesn't give that property, that property is not provided.
It'll just be harder to damage the armor if you track that sort of thing in your games. The character will be damaged as normal if a hit is successful.
Some Magic Armor does grant resistance, but they explicitly state that's their function
Some examples of such armor that does grant the wearer resistance to damage are: