Indeed, they have been, but until the 1970s, seminaries took care to weed out candidates who just wanted to be “with the boys.” Many were sent home, with the excuse being that he was “nervous.” As far as those continuing, the Church has radically changed the rules since 2001, but we have to contend with those already inside. With the collapse of morale in the ‘70s, with the departure of many priests to get married, many came in. Attrition is the best policy since most are not, in fact, malefactors. So that it presents a real problem. Unlike the Episcopal Church, however, the foxes have not taken over the hen-house. The Church has not capitulated on the issue of the morality of homosexuality and is adamantly opposed to gay marriage. As to prosecution, better look to the civil authorities.
Sheep in wolves clothing might better say what they are, and these unfortunately are far more difficult to detect as they hide behind the cloth they wear. At least one can tell the difference between a fox and hen. This the catholic church faces is simply far more diabolical...
I recall a Pope mentioning satan had entered the vatican and how disturbed he was to have evidence of such. Let's hope the current pope will be unafraid to take stronger measures than have been in the past. Somehow I imagine that he will or this plague will continue.