"Because I think, I am" just implies that I exist because I think. This implies that thoughts are a necessity for existence. I am saying that is not the case and thoughts are not a necessity for existence. What you inferred, although true, is not the correct implication of the statement.
I was reading it more similarly to "Since I think, I am" which would be closer to "I think therefore I am" than to "I am because I think", though perhaps that's giving it too much slack, or perhaps its coming from a native language where word order is more flexible than in English.
Natural language is vague and allows for many possible interpretations of short phrases. The one that is more applicable to Descartes quote is something along the lines of "me thinking proves that I exist". This, of course, says nothing about thoughts being a necessity for existence.
Yeah, sorry I missed all of this. I agree that thinking is almost certainly not necessary to exist. I probably could have written it more as "Because I think, I can be certain that I exist"
