There's talk going 'round that the motivations, in retrospect, were to change the Priesthood from within outward. If enough homosexuals were included in the Priesthood, more then would be and the Priesthood would change to accommodate homosexuality in the Catholic Church.
Such that, they made a start at that and we see the terrible damage that resulted. You asked as to why anyone with certain "demons" would even want to be in the Priesthood and it's like asking why a pedophile wants to be a scout leader, or why a man who beats up females would want to marry or why a drunk wants to drive a car, or why people smoke and...
The issue about the Priesthood, however, seems to have been very sinister (not that some in that previous list are not), and that was to change the Catholic Church from within to then become not Catholic but liberal-homosexual-anything-goes-do-it-if-it-makes-you-happy, etc, organization to talk about past lives and devinations and astrology and...
I exaggerate a tad but the process seems to have been one to place homosexuals in a greater area of influence in the one Church that has consistently confronted homosexuality in a Scriptural sense. Albeit failed terribly to protect and enforce during the years that followed but now catching up. I think the failures were, in fact, the results of the homosexual influx to the Priesthood, to state the obvious here. I'm sure many would agree...we had an increasing atmosphere of laissez-faire as to behaviors and accountability and, well, the wages of sin...we saw the results.
You understand the concept of incremental degradation of the soul. Interesting.