If you have a soy allergy and are highly allergic to soy then you should avoid soy sauce.
If you're just slightly allergic to soy then eating a tiny bit of soy sauce should not be a problem but be aware that you can get affected by the soy sauce when you are allergic to soy sauce.
I would just recommend staying away from soy sauce when you have a soy allergy.
When you're allergic to soy you should avoid any food contain soy including soy milk.
Eating or consuming anything that contains soy when you're allergic to soy can cause the allergic reaction to the soy.
So it's best to avoid the soy based food products when you do have an allergy to the soy.
But if not you do so at your own risk.