OK let's look at the evidence:
I am very glad to have this particular opportunity of saying a word about some of the things in which we agree with our Masonic friends, because we are speaking in a building dedicated to Masonry, and we also are Masons. I am a Freemason." Charles Taze Russell
What part of the bold text do you not understand?
This was part of a speech that he made back in the early part of the century. It's in a special 1913 Convention Report of the Internal Bible Students. Under the subject of "The Temple of Gods" in a discourse by Pastor Russell reported verbatim on pages 120-127.
Not enough for ya? check this out:
Guess whose tombstone that is?
Oh did you also know that the Russell family founded the "Skull and Bones" secret society at Yale University? Never heard of it? Try googling it. I'll give you a hint. It's not a christian society.
Now show me the evidence that he wasn't a mason.