be subject to / be subjected to

Sorry, i really don’t understand your examples. In thinking of others by myself, it would appear you are correct, “subject to” and “subjected to” are identical in meaning but are just used for different nouns. For example.

A person may be “subjected” to something (He was subjected to cruel and unusual punishment)
For the most part, all other things may be “subject to” something else…I don’t know why but to say “John was subject to cruel and unusual punishment” just seems incomplete to me. It doesn’t “ring true” like the first example.

In meaning, they both convey the idea of not necessarily being dominated by but rather being exposed to, being susceptible to, or not having the ability to stop something from happening (ie. A nation which is subject to violence may have a poorly skilled police force, or for whatever reason, has difficulty in suppressing the violence)

Hope this helps.