"Am I wrong to feel deceived?"
Morally, most likely, no. Legally, based on information here and without seeing the original ad, yes. The default position of any used item being sold is "As Is" regardless of that being said in the ad or not.
https://en.wikipedia.org/wiki/As_is
If a buyer makes assumptions about the item being sold, he is also assuming responsibility as well should he happen to be wrong.
Some sellers will tell everything even down to the most insignificant detail. Whether it is intentional or just their nature, other sellers will say very little. Nevertheless a seller is only wrong legally if he lies or gives misleading information.