Homosexual conduct is a sin. Sinning makes one a sinner. It does not mean that one can no longer be a member of the Church.
Excommunication is reserved for certain grievous sins (like procuring an abortion) which are specifically spelled out in canon law. Homosexual acts place one outside of the grace of Christ, but not outside the Church.
Whoa. You'd have to 'splain that one to me, if you've the patience.
And isn't openly saying "Ptui! on God's declared law of sexuality!" excommunicable?
Dan