I am very interested in this thread as I am a committed Christian and active Freemason.
Those "Christians" who hate Masonry usually have two major objections:
1. Because Masonry accepts men of all faiths, it is "indifferentist," i.e. it teaches that all religions are equally good and it doesn't matter which one you espouse. (Not true of course. Masonry does not say that all belief systems are true, which would be absurd. Rather, it refrains from passing judgment on their relative merits, leaving that to the individual Brother. It does require belief in a Supreme Being, and mutual respect and tolerance among those with different beliefs about Him.)
2. "Masonic theology" is incompatible with Christian theology (or the "Masonic God" is not the Christian God).
Of course there is a huge non sequitur in all of this: How can Masonry have #2 - its own theology - which would indeed make it a religion unto itself, and still be #1, an interfaith brotherhood? Wouldn't it have to force Christians, Jews, Muslims, and others to renounce their respective faiths and convert to the worship of the "Masonic God" as defined by "Masonic theology"? Then religious tolerance, which indeed is a Masonic principle, would go out the window.
Beyond this, there seem to be zillions of sites on the Net that pretend to objectively examine the question "Can a Christian be a Mason?" (or a Mason be a Christian). This too is idiotic since there is a simple answer: there are already hundreds of thousands, if not millions, of Christian Masons in the world. They have even set up their own organizations, among them the York Rite and Swedish Rite. Asking whether a Christian can be a Mason is like asking whether a woman can be a fighter pilot: if you really want to know, don't sit at your computer and spew ignorant nonsense; rather, look around and see if they exist. Yes and yes. Case closed.
However - and this is the crux of the matter - the people who are trying to hound Masons out of the church can't be reasoned with. Logic didn't get them into their anti-Masonic hatred and it won't get them out. But that doesn't make them any less toxic; in fact, it makes them more so. I have not made my Masonic membership public knowledge at my church for fear that an anti-Mason might stir up animosity against me. I'm not sure if this is being diplomatic or just cowardly. I don't want to go to another church, I love the one I'm in and have good relationships there. I am sure most people, even those who don't like Masonry, would see me as the individual I am rather than as a cartoon-character villain, but it only takes one person spreading hatred and suspicion to cause a lot of heartache.
In any event I am always interested in what others have experienced.