Why is Soy Sauce (Tamari) Not Keto?

Everyone says you cannot have soy sauce on the keto diet. I get why - the wheat, in the Shoyu (typical) soy sauce. I dutifully followed the recipes and used Coconut Aminos instead. But I just checked the carbs of all 3. Tamari (no wheat) has 4.8 net carbs per 100g and Coconut Aminos have 7.0 net carbs per 15g. (That equates to about 45g per 100g - or almost a whole days worth off carbs). What the heck is going on here?! So much for low carb. I must be missing something. What man I missing?