𝘢 𝘯𝘰𝘯-𝘛𝘳𝘪𝘯𝘪𝘵𝘢𝘳𝘪𝘢𝘯 𝘊𝘩𝘳𝘪𝘴𝘵𝘪𝘢𝘯 𝘥𝘦𝘯𝘰𝘮𝘪𝘯𝘢𝘵𝘪𝘰𝘯
If a denomination denies the Trinity, it is not Christian.
The Christadelphians are a cult, at best. Like the JWs or the Mormons.
They are not Christian.
"Cult" is kind of a loaded term in our time because people usually use it casually to refer to, basically, "a religion I don't like."
More accurately, as non-Trinitarians who claim to profess Christ, the Christadelphians are a pseudo-Christian sect.
Beyond that, any organic org which claims to uniquely be the one true church is a cult. The Biblical body of Christ (Colossians 1:18) is the one true church to which He is married, (Ephesians 5:25) the "household of faith," (Galatians 6:10) for it uniquely only and always consists 100% of true believers, and which spiritual body of Christ is what the Spirit baptizes every believer into, (1Co. 12:13) while organic fellowships in which they express their faith inevitably become admixtures of wheat and tares, with Catholicism and liberal Protestantism being mostly the latter.
I agree sir. If they deny the Trinity, they are already behind the 8 ball.