My father once gave me some good advice:
"Being the strongest, or the most wealthy, or having the most girlfriends does not make one a man. Doing what it takes when you need to, without hesitation, to help, support, and protect those you love, that is the true mark of a man."
That being said, I believe Father's Day is to honor true men, who do what is neccesary and give up some of their own wants so that their family can enjoy life and prosper. Anyone with any sense can see that someone who is not a good father should not be honored in Father's Day. The purpose of the thread was to acknowledge all those who do what needs to be done. Getting a girl pregnant and having her bear a son does not make someone a father in my opinion. The father is the one who helps the girl raise the child and treat them both well, in my opinion. So regardless of who's genes the child carries, if you take a major role in the development of that child, you are just as deserving of a Happy Father's Day as a good father who raises his own offspring.
So really...lose the attitude, there's no need to denounce what is meant as a wishing of blessings to honor great men who do a lot. Leave your emotional baggage at home.