Stuff and nonsense! All men who believe in God are welcome to become Masons.
Catholics are welcome but from what I understand, the Vatican prohibits practicing Roman Catholics from joining any group which has a code of secrecy.
Not long ago I heard the story of a practicing active Roman Catholic priest who was a Mason.
Oh, I know first-hand that there do exist Catholics who are free-masons. The question is whether they can be Catholics in good standing. Certain state chapters (terminology?) of Freemasons are fairly freindly towards Catholics. Some are even accused of trying to infiltrate Catholicism. Many are expressly anti-Catholic. But freemasonry, itself, probably emerged from Knights Templar who were prosecuted by the Catholic Church for war crimes during the Crusades; the antipathy is most certainly two-way. As many of the Knights Templar refugees fled to the mountains of Switzerland, it's not hard to imagine that they heavily influenced Calvin and other anti-Catholics.
There is a Masonic lodge right here in Los Angeles county that has a Catholic priest as a member. It is not generally known, but the Church has no real objection as long as you don't go into the higher degrees. The Scotish Rite in particular.
Freemasonry prohibits "Papists" (or even former "Papists") from advancing beyond the first few degrees.
You can be a catholic, or a baptist, or a presbyterian, or whatever, but what you cannot be is a child of God.