There was a time up until the 1950's when the WTS said they were not a religion at all. Then in the 1950's they changed that to "false religion" and "true religion" saying that the WTS was the only true religion. https://wol.jw.org/en/wol/d/r1/lp-e/1951607
"Why has the Watchtower Society suddenly approved the use of the word “religion” relative to the worship of Jehovah’s witnesses?—P. L., New York.
We are not trying to make a new language, but we want to use the language we have to the honor of God’s name, and do so with as little confusion as possible in Kingdom preaching. In the English language the word “religion” means the service or adoration of God or a god, as expressed through certain forms of worship. So the religion may be either true or false, depending upon both the god being worshiped and the form or manner of expressing the worship. If we practice the true form of worship of the true God Jehovah, and if we are speaking the English language, then when discussing our worship we may properly use the English words that will so limit our meaning, namely, “true religion.”