Gay Marriage and the RC church

As a heterosexual male, happily married for over 40 years, I may not be best placed to give a view on gay marriage laws. However, I am absolutely incensed when I hear the Roman Catholic church pontificating about how wrong it is for two people in love to make a public commitment of their love by marriage. What right have they to be so "high and mighty" when their record on sexual morality (child sex abuse, priests who are celibate and know little of sex and its value in a loving relationship, etc)  is, frankly appalling!