Of course, I could not refrain to at least throw a high level answer out there to get people to dig in and ask a few more questions of history and the facts.
Here it is (and there will be much more to come as time goes on):
First of all, I want to say that I like your blog with its thoughtful input.
As a missionary in Brazil, my mission President (a convert and the first black 2nd quorum of the 70), Helvecio Martins was a former Mason and this topic got kicked around alot back in the day. My wife and I have dug into this one, as well.
For me it is very simple - and it is the same question that always comes up about our doctrine as the only church of a "restorationist" nature where we claim not to have "new wine put into old bottles" but to have "new bottles", etc where others are either from the mainline religion that departed from the new testament church to the point that there is little resemblance to structure, doctrine and priesthood type and authority. The only other option is belonging to a group that protests the doctrines and beliefs of the main body. We claim that our church is the same as the church that existed when Christ was upon the earth and that the ancient church (other than sacrifice by the shedding of blood as a type and foreshadowing of Christ's sacrifice) is the same basic organization that existed with the earlier peoples of the earth (house of Israel). In other words, the answer to the chicken and egg argument (in regards to the temple ceremony) is that it was always here and practiced by ancients (including those at Qumran) in the day when the original temple was built by Solomon by those of the "masonic" guild. In order to build the temple, they had to have the higher priesthood with its endowment given to them and thus were initiates to what every one who possessed the higher priesthood had. This knowledge, like everything was watered down through apostasy over hundreds of years and then was lost to history and then re-obtained when the Knights Templar escavated Jerusalem during a crusade to re-Christianize the Holy Land.
Through a series of events, this was taken back to Europe and then spread to the U.S., etc. where Joseph Smith happened onto it and asked questions and was given the answer that we know as our modern temple endowment. I have studied just enough of the Masons (even got a Junior Achievement award and dinner in their 'endowment room' unbeknownst to me at the time) that I know that they have portions of the truth and that it definitely based off of the original 'masons union' that was given this sacred info in order to qualify in the building of the temple. Thus the name, the builder's symbols, and the most striking is their two pillars Boaz and Joachim still used in their entry way to the building - same as the two bronze pillars of Solomon's Temple.
As always, the Church is accused of imitating something that already existed - when all I want to say is thank you very much for noting the obvious - and then asking the question, would you like to be part of the restored original, or would you like to continue with the cheap and mostly unrecognizable knockoff that you are currently part of? I prefer fresh earthenware myself, thank you very much.
Hope I have not offended anyone - but I had to jump in here and throw my two cents in. Glenn Beck and many others attend our Sacrament Meetings and have felt something unusual and special and that has motivated them to make changes in their lives to be a part of that. I go to the Temple and that same Spirit is there - but ten fold. I have a deep and abiding knowledge that the Temple IS The House of the Lord because of that very Spirit that resides there. I will not even go into the spiritual experiences that I have had that further cement that witness. It is the 'Lord's University' for those that prepare themselves spiritually. Many people have a spiritual "grade school" education and choose to mock those who have seen the beauty of learning and who seek higher education. Unfortunately, for many who choose to throw stones at things they know not of, they cannot even comprehend because they will not take the first step forward in faith. The gospel is truly line upon line and precept on precept until we all come to a full knowledge in Christ.
I sometimes come across as arrogant in how I speak but I truly love all men and my only desire is that they find the truth that makes my life and joy full and gives it meaning and full purpose.
I am not trying to be rude by not replying but my time is limited. I hope this reply sparks further study and learning.