I can only recall having this distinction be made as part of "hate the sin, love the sinner" perspectives. Perhaps the argument is advanced by other groups or in other contexts, but I don't recall have seen that.There is to be made a helpful distinction between homosexuality and homosexualism.
Homosexuality: a condition of personal identity in which a person is sexually oriented toward persons of the same sex.
Homosexualism: explicit and overt homosexual practice.
The latter is what a lot of people object to; not the former.
Mind you, since the government doesn't legislate against adultery,ergo it shouldn't do so against homosexualism; even I would disagree with both.
IMO, the underlying notion has some utility, in that a person's thoughts, ideas, fantasies, etc, can be separated from their actions. A person who declares a biblical belief in loving their neighbours and charity for the needy while selfishly and greedily seeking to live a lavish lifestyle, refusing to help others, and advocating racist rejections of others should be judged y their actions rather than their professed ideals. Similarly, a person who imagines or dreams of violence but does not act of those thoughts is to be commended for their restraint.
However, there are also circumstances where there is no utility in a thoughts and desires v. actions distinction. Homosexuality is a normal variation in sexual orientation, seen in many species other than humans, and to suggest to a gay person that it is ok to feel same sex attractions but it is wrong to act on the very human needs for affection and intimacy is not acceptance, nor love, nor support or understanding. It is, perhaps, profoundly ignorant to suggest that acting one should not act in line with one's nature in such a fundamental part of human existence, or perhaps callous, or (in some cases) it is a manifestation of hate.
Sexual orientation may evolve over a person's lifetime but there is no legitimate medical or scientific evidence that it can be changed. To suggest (as some do) that same-sex attracted people have equal access to marriage as they are free to marry a person of the opposite sex makes a mockery of what the institution of marriage means. To suggest that same-sex attracted people can only be acceptable to a religious community through celibacy and the denial of a core aspect of their nature is not only judgemental but also hateful - an insistence on suffering over something natural, normal, and out of their control.
Objecting to homosexual actions, undertaken consensually and privately by adults, is not a manifestation of acceptance or a value-neutral perspective on homosexual orientation. The logic is akin to saying that living in water is fine but breathing under water us not, and so accepting whales whilst condemning fish, unless the fish learn to breathe only at the surface and never underwater.
Humans are sexual animals, with an urge to express themselves sexually. As a society, we lay down laws to protect vulnerable groups (like children) from harm. We should punish those who force sexual encounters on the unwilling , rape being a violation regardless of the sexuality or behaviours of the perpetrator towards their victim. We also recognise that sexual behaviour is not solely about procreation and the desires and actions of consenting adults in privacy are areas that society should not, in general, regulate. Religious groups (of whatever faith and belief system) have the right to express views on matters of personal behaviour and even to exclude members from their groups should they wish... but they don't have the right to impose their views on non-members. They can advocate and then abide by societal decisions. Sadly, it still happens that groups or their members believe that their right to their own beliefs extends to a right to judge others, to act as if their values extend everywhere except inside the bodies of those who disagree. Telling someone who does not share your faith that they will be judged and punished for being who they are is often an unwelcome intrusion. Telling a young person struggling with their understanding of themselves that they face rejection and even damnation for express how they feel is not an act of love; it is a brutalising strategy used in an attempt to force them to compliance, one that has done massive harm to many who struggle to achieve a level of peace and self-acceptance.
@dan964, you are free to hold your beliefs and to express them. Unfortunately, I see the distinction that you raise as unhelpful and harmful. I do not accept that there is a meaningful separation between "I accept person X as a gay man, but only so long as he never acts on that orientation" and "I don't accept person X because he is a gay man." The former is not a statement of tolerance or an expression of love for one's neighbour. Rather, it is a demand that someone suppress their nature to be acceptable in your eyes. It is as unreasonable as expressing acceptance for an immigrant so long as they set aside their cultural heritage and background and be a "true" Australian, or of acceptance of a person from a different faith. so long as they convert. Acceptance of a person's homosexuality (or bisexuality or gender identity or ...) is not meaningful if it comes with a requirement that that person not express their identity in ways that you disapprove (or object to, as you put it above).
I can accept that it was not your intention to offend in making your statement, and I know that your perspective is one shared by others. However, it is offensive, in my view. Given the size of the LGBTQIA+ community and its allies, I suspect I am not alone.