My sense (reflecting on previous internet discussions going back a few years now) is that Leviticus 18:19 is highlighted because a presumption is made that this is one proscription in a chapter of proscriptions which is uniformly not obeyed (or, at least, widely disobeyed) by that community of Christians who otherwise argue that Leviticus 18:22 (and, of course, a number of less or non-controversial commandments in the chapter*) should be obeyed.
Some questions arise:
(1) Suppose all the disobeyers of Leviticus 18:19 got their act together, repented and obeyed this proscription. Would that mean that all the disobeyers of Leviticus 18:22 would also repent? (My hunch, of course, being that a different line of hermeneutical consideration of 18:22 would then be pursued!)
(2) Whether or not the connections via the Greek version of Leviticus 18:22 and New Testament passages holds good (as referred to by me in a post below), I think it unarguable that, to the extent that the NT says something about same sex sexual relationships, the NT takes a 'dim view' of such relationships, in line with Leviticus 18:22 (and, yes, mostly with male-male same sex sexual relationships in mind). This of course is unexceptional as an observation inasmuch as virtually all the NT says about ethics of human social behaviour is in line with OT commandments. Does the NT 'reinforce' or 'underline' the ongoing application of Leviticus 18:22 for the Christian community? If so, is this reinforcing or underlining of Leviticus 18:22 a dimension we need to consider as a binding of the commandment for the Christian community in a way in which Leviticus 18:19 is not (because not further attended to in the NT)?
(3) Suppose we agreed that Leviticus 18:19 (i) no longer applies to Christian readers of Scripture (ii) the lack of continuing application raises the possibility that other proscriptions in Leviticus 18 no longer apply? [Logically this must be the case!] Does it thereby follow that any of the other proscriptions are thereby remitted? I suggest the answer is "No." We would not suddenly be freed to sacrifice children to Molech or to sleep with our neighbour's wife. We would, of course, be in a situation where the mere statement of a proscription in Leviticus 18 was not sufficient in itself to yield the definitive, everlasting conclusion, "Do not do X applies to Christians." Other considerations would need to be brought to bear on the discussion. In the particular case of 18:22, that, I suggest would include consideration of (2) above.
In short: I think there is an important hermeneutical discussion to be had about 18:22 in the respect of the whole of Leviticus 18: the questions posed here are questions, but, at least on an initial response to the comment made about 18:19, I am not convinced that 18:19 is the 'pivot' on which the discussion turns.
*None of us know any sane person who argues for bestiality or child sacrifice to Molech!!