True, but a heterosexual or a homosexual who persistently takes each thought captive and refuses to "go there," even in their minds . . . imho, is not sinning.
Abstaining from thought sins and active sins is a discipline, certainly--evidently one that trains us to be overcomers.
I suppose one could SAY that overeaters, alcoholics, homosexuals, playboy studs, workaholics, netaholoics, . . . the list is endless . . . are all grossly sinning just to notice food, a beer ad, a beefy guy, a shapely gal, work to do, websites to scan, . . .
but I don't think God sees it that way.
Feeding in our mind and rumminating on possibilities with such sin options is another matter.
And how many of these folks do you know who actually do that? I doubt there are many. I know they can be redeemed through the blood of Jesus Christ, but the thought life is always in motion. We sin just by being alive because of the sin nature within us. I believe a homosexual can be delivered of all that and set on a new path.