mormon missionaries will tell people that you only have to pay 10%

which, by itself, is a shock for most people, but what they DONT tell you is that once you get to the temple you have to agree to the law of consecration which requires you to give 100%, that you have to:

"covenant and promise before God, angels , and these witnesses at this alter, that you do accept the Law of Consecration as contained in the Doctrine and Covenant, in that you do consecrate yourselves, your time, talents, and ***everything with which the Lord has blessed you, or with which he may bless you***, to the Church of Jesus Christ of Latter-day Saints, for the building up of the Kingdom of God on the earth and for the establishment of Zion."

"mormons only pay 10% (tithing) of their income" is a whopping lie =) the figure is missing a zero--100% (if the church requires it of you)

the rest of the story FAIR deliberately left out about joseph smith's moon men beliefs

oliver b. huntington's testimony about joseph smith's teachings about men on the moon:

As far back as 1837, I know that he [Joseph Smith] said the moon was inhabited by men and women the same as this earth, and that they lived to a greater age than we do -- that they live generally to near the age of a 1,000 years.
He described the men as averaging nearly six feet in height, and dressing quite uniformly in something near the Quaker style

FAIR'S main response (in addition to the "speaking as a man" copout):

However, it should be remembered that this concept was considered 'scientific fact' by many at the time.

but FAIR intentionally leaves out a rather key part of that testimony:

"Astronomers and philosophers have, from time almost immemorial until very recently, asserted that the moon was uninhabited, that it had no atmosphere, etc. But recent discoveries, through the means of powerful telescopes, have given scientists a doubt or two upon the old theory.
Nearly all the great discoveries of man in the last half century have, in one way or another, either directly or indirectly, contributed to prove Joseph Smith to be a Prophet."

FAIR is just doing what dallin oaks describes as the mission of official church literature--misrepresentation (lying):

Balance is telling both sides. This is not the mission of the official Church literature

see also Early Mormon Leaders on the Inhabitants of the Sun and Moon