Cooking carrots makes them filly digestible, so you lose the antiseptic effect, and also get exposed to tons of beta-carotene, which is sadly anti-metabolic.
"Dr. Ray Peat suggests that beta-carotene can interfere with thyroid function and may not effectively convert to vitamin A in some individuals, particularly those with low thyroid activity. He recommends avoiding excessive intake of beta-carotene and focusing on obtaining vitamin A from animal sources instead."