Freemasons practice syncretism which is the blending of different religious beliefs into a unified whole. This is evidenced most especially by Masonry’s religious rituals which gather men of all faiths around a common altar, and place all religious writings along side the Bible on the Masonic altar. This is also demonstrated by the Lodge’s prayers and its unique names and symbols for God and heaven. Syncretism is the logical consequence of indifferentism.
I’m a Freemason, and this critique is a very valid concern. Freemasonry was born in a time when religious differences were severe - so we had to set aside those differences in order to be ‘Brothers’ inside the lodge. I think modern Masons should be careful not to cross the line - I know in our lodge we’re very careful to show respect to the religious beliefs of our members, but to not make any false equivalences. Our names for God are an attempt to not cross any religious boundary.
In our defense, to be a Mason, one of the oaths is that we are to frequent our house of worship. In addition, Masonry absolutely denys that masonry has any part of salvation.
That said, if you’re Catholic, I would highly recommend the Knights of Columbus. They have all the silly ritual and silly hats that Masons do, all the good works, and none of the guilt.
Our Lodge does have several Catholic members - and for myself, I would take no part of anything that was remotely contrary to my Christian faith.
I would also like to point out that Freemasonry in the US, Canada, England and most of the Commonwealth is different than Freemasonry practiced on the European continent - they really are worthy of all the suspicion; especially lodges in France and Italy.
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EDIT:
If I can answer the OP’s question. From a Catholic perspective, Freemasonry is considered occult and there’s a papal encyclical that forbid membership by Catholics. As a member of Freemasonry, I can tell you that while I enjoy the fraternity and the rather odd history and rituals, I would say that you’re not ‘missing out’ too much. Don’t be afraid of Masons, but at the same time, I would urge you to follow your Catholic teaching.