Religion is sometimes defined as belief in a particular deity. In that respect a great many Protestants have the same religion as us, the worship of the Triune God who revealed himself most completely in the Incarnate Word.
But a religion is more aptly defined as an organized system of beliefs, ceremonies, and rules which promote a particular way of life in service to that deity. It might admit of some diversity among different cultures, but always in harmony and without conflicting truth claims. In this respect, Protestantism cannot be considered one religion, let alone the same as ours. If we say that Protestantism is the same religion as ours, then we admit that God revealed many conflicting truths; in short, we make God a liar and sower of confusion, which is blasphemy.