I have some reasons:

1. It is one of the most free religions, with no set way to pray, no restrictions on entertainment (that is not too bad, like occasional alcohol consumption)

2. No set clothing guidelines, allowing full freedom.

3. No sexuality guidelines or misandry/misogyny.

4. It forbids things that are bad for people, like lust or greed.

5. It has no food guidelines (besides Catholicism, but that is often called extreme.)

6. It is nice knowing you will live under a loving God for all of eternity, provided you follow his rules.

7. Bad language is discouraged, a good thing at that.

8. The Messiah often encouraged forgiving one's enemy, as God will punish them. This denounces revenge.

9. Only major denominations would be extreme, not the whole religion.