It is very important to distinguish between
1) homosexualism/homophilia,
2) homosexual activity, and
3) "homosexuality."
1) Homosexualism is an ideology which claims that homosexual activity and "homosexuality" are OK, even OK with God; that they are good. Homosexualism is a sin against the Truth, the truth of faith, distorting the moral law, an attack on the Author of man and woman Himself; it is an attack on God Himself who said "Thou shalt not commit adultery." Matthew 5:27. The homosexualist says "Thou canst commit adultery." It places a false lord over the Lord Himself. That is the mission of Dignity. Dignity claims to serve two masters: Satan and God. If you avowedly love sin you hate God. "No man can serve two masters," says the Lord. Matthew 6:24. Homosexual affectation is a form of homosexualism.
Homosexualism has no place in the Catholic religion and should be eradicated at all levels.
2) Homosexual activity is another category of sin. That is the decision to do the sinful homosexual act and/or actually doing it. There are people who fall into homosexual sin without being ideological homosexualists or "homosexuals" in temperament, i.e. with no homosexual tendency at all. This is the action (whether in the will or in physical activity or both), plain and simple.
This sin, if repented, need not, in itself present an impediment to sound doctrine and upright moral life, as long as there is no danger of scandal, leading others into sin.
3) "Homosexuality" is the male on male or female on female attraction, an unnatural venereal attraction; as in bestial desire or incestuous desire in which a man desires venereal pleasure with animals or with his own kin respectively. "Homosexuality" is a tendency, an emotional compulsion which need not be present in the homosexualist/homophile who simply approves of that disordered emotion and/or activity. The person afflicted with the homosexual tendency, the "homosexual," need not be a homosexualist, he need not even acquiesce in the least to that personal disorder. In fact, there are many persons afflicted with the homosexual desire who totally reject it; they never act out on it because they know it is evil; they follow the Truth and the Law of God, which is the same thing; they love and follow God, Jesus Christ; they are chaste; they do not sin; they are living martyrs of an unwanted tendency against which they manfully fight. That is the mission of Courage.
The homosexual tendency should be considered an impediment to holy orders and to any type of leadership in the Church because of the obvious conflicts it creates for the "homosexual" and the scandal which those conflicts cause, leading many into sin.