Is sitting on a camel in a dream inauspicious?
I think you're being confused.
Riding (or sitting on) a camel is not considered inauspicious. But having dreams about riding a camel is certainly considered inauspicious (for the person who is riding it in dreams) (as it is considered to be a sign of approaching death).
Analysis of good/bad dreams and good/bad omens are given in detail in the Agni Purana.
I'm quoting from the the book Essence of Dharma Sindhu:
A fairly detailed analysis of dreams and omens is given in Agni Purana. Dreams are good when they involve mountains, Palaces, snakes, riding horses or bulls, white flowers, trees , possession of arms and many heads, triumphs in battles,wearing garlands, witnessing Solar and Lunar Eclipses, Stars, Sun and Moon, eating rice pudding, drinking wine or blood, eating meat, milking cows and buffaloes, blessings from Devas and Brahmanas, Coronation, one’s own death or cutting off the head, one’s own house burning, playing musical instruments, climbing trees, clear skies,wet clothes and so on. Bad dreams are a shaven head of one’s own, wearing shabby clothes, drinking oil, angry Gods or Brahmanas, steep falls from heights, killing snakes o r animals, playing with monkeys,weddings and singing. Dreams portending death include the sights of hair, fire, serpents,dried up rivers or water bodies crooked noses, long ears, weeping lefty eye, a metallic face, black tongue, riding camel or donkeys bound to Southern direction, ...
For example, from the above passage, having dreams about drinking wine, blood are considered good. But actually drinking those substances will be considered bad only. Similarly here.
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