おいしいようだ おいしいみたい おいしそう

Similarity or hearsay – Learn Japanese
While "おいしそう" seems all right, why does Tae Kim say we can't say 「おいしいようだ」? To say that something looks tasty is like saying, "This dish apparently is tasty," which can actually be kind of rude.
He also says we can't say 「おいしいみたい」to say that something looks tasty because it implies that, in actuality, the food might not be so good.

Both ようだ and みたい can't be used for a dish you are really seeing, since these are used for a logical deduction. For example, あんなに行列ができるなんて、あの店はおいしいようだ/みたいだ is valid when you see that a line is formed in front of a restaurant. I don't think these expressions sound rude. It's just odd.