Hi, Alexander —

Thanks for your questions.

As Christians we have a duty to participate in our own governance. That includes politics.
Some people have a specific call to be involved in politics. We need Godly men and woman to take a leadership role but that doesn't mean that we allow politics to corrupt our principles. 

Finally, just about anything can be the devil's playground.

Now let's deal with homosexuality. The Church teaches that homosexual acts are sinful. However, if a person has this disordered inclination, that doesn't make (him or her) a sinner until they act on their disordered passions.

Homosexual acts are sinful for the same reason artificial contraception and masturbation are sinful. No life can come from the act. Our sexuality is a gift meant to be expressed between a husband and his wife. While a married couple is free to engage in relations because it brings pleasure, they must remain open to the life-giving nature of this sacramental act. That's right:
sex between husband and wife renews the sacrament of Marriage; it is a holy thing. That is why it is wrong to artificially separate the unitive (loving) aspect from the procreative aspect.

Homosexual acts, like masturbation are sterile and therefore like artificial contraception they are grave sin.

As for the logic behind it, Come on! How graphic do we need to get. It's like putting together a piece of furniture. Insert Tab A into slot B. Homosexual acts are by definition illogical. At best, they are based on feelings — at worst, simple lust. Nevertheless, logic transcends feelings, even if that feeling is love, and logic dictates that the biological reason for sex is procreation.

As for Jesus' birth being celebrated on December 25.

When we celebrate holidays, the date we celebrate them, falls into the category of small t traditions. These are not Teachings or part of Sacred Tradition. Rather they are traditions that we practice. They are not part of Divine Revelation, nor are they doctrine, and whether you believe Jesus was born in July, September, or December, it doesn't have any bearing on your salvation.

John