That is the question I have asked both in the past and received the same hooey for an answer.
Can't say as I blame them; Cult members don't like to name the devil that spawned them.
So using scripture alone is cultic to Catholics?
It is not the Catholic Union Association of Churches of the Roman Rite, which is a large denomination of local churches governed by assent to the bishop of Rome, the RCC. It is unquestionably not the only existing church denomination, nor does its exclusivity deny the reality of a plethora of independent local Bible fellowships, all claiming the leadership of Christ.
So don't ask that absurd question. No intelligent person would pay it much attention. It's just a mud-slinging slur, not a real question looking for a sincere answer.