There's a reason why people view certain groups as cults and others as religions that has nothing to do with how acceptable they find their belief system, but rather how that belief system is acted out in the world.
Take Scientology vs Christianity on a few basic points.
- Take the beginnings of each religion. Christianity was started by a small group of Jewish people who endured hundreds of years of horrific persecutions from both Jewish and Roman society before becoming accepted. Considering there's no proof that any of those people gained any real power or wealth from being involved in Christianity, it's hard to argue that they had ulterior motives outside a genuine belief in what they taught. Alternatively, L. Ron Hubbard is quoted numerous times saying that the best way for him to become rich was to start a religion.
- I am a Christian of the reformed baptist persuasion. If you ask, I will tell you exactly what that means, every single detail of my theology. If you ask I will give you a Bible, the basis for my faith. I can show you confessions of faith from hundreds of years ago outlining the major doctrinal teachings of each major denomination in Christianity. There is absolutely no secrecy around my faith or the faith of the major Christian denominations. You can visit my church any time you like Alternatively, Scientology is completely shrouded in secrecy. There's different 'levels' of beliefs. All that stuff about thetans and Xenu was only ever found out due to leaks and whistle blowers. The Church of Scientology does not advertise what it believes and will not tell you unless you reach a certain level of their faith. Which brings me to my next point.....
- Most (I say most, as unfortunately there's a large number of Christian churches today who don't follow this. To me, that's the encroaching of cultist practices into the church) Christian churches do not require any monetary contributions of any kind to participate in the religion. That's not to say they don't ask for funds, because like everything, they need a certain amount of money to simply exist. You can go along to most churches, never give a single penny, and still partake to the same extent as the person who may be giving $1000 a week. You can still partake in the sacraments (in the Protestant case, communion and baptism), you can still listen to the sermons, you can still sing the hymns, and you can still have fellowship with the other church-goers. This is patently not the case in Scientology. Monetary contributions are required to participate. You can't join unless you give them thousands of dollars for an audit. You can't progress unless you continually provide thousands of dollars. There is an enormous amount of evidence of people being extorted and blackmailed for ridiculous amounts of money.
There are real and significant differences between Christianity and Scientology that extend way beyond "people only accept Christianity because it's 2000 years old, whereas Scientology is new", and "I'm a Christian and therefore Christianity is good, but I'm not a Scientology so Scientology is bad".