I'm sorry you see a contrast between the two positions. I don't. Perhaps I can clarify.
If you walk into a first date, and proclaim every negative thing about yourself in the interests of being "upfront", you likely will never have a second date. Swinging, to most people who have never been involved in it, would strike as a negative with very likely the vast majority of women. If I were in this person's shoes, I wouldn't bring up swinging on the first date (!). Non-monogamy is not a must have. It's an interest, and something I enjoy. If it never happens, it never happens. I would not feel my relationship with a woman is compromised in any way because she doesn't want to swing.
This is radically different than me being attracted to a person whom I presumed from every cue to be a genetic woman, only to find out she is a pre-op transwoman. If I'm looking for a genetic woman, and you're presenting yourself as a genetic woman only to find out when we get to the point of being in bed and you've already given me oral sex, that you are not, you have been deceptive in who you are. You can't contribute to the relationship in the same way, that is something that can't be "if it never happens, it never happens". I don't have a problem with someone being a pre-op transwoman. I do have a problem with them being deceptive about it to the point where we've already had sexual acts together before I find out.
I had the former come up with my now wife. Prior to being with her, I had been in a poly triad. I was romantically involved with a married woman, and was friends with her husband. He knew and approved of the relationship. Some time after that relationship, I met my wife. A few weeks, a month into the relationship I told my wife about this prior relationship in the poly triad. I wasn't going to not tell her prior to getting married. My wife didn't approve, and felt I was causing this other woman to cheat, spoiling her marriage, and contributing to the breaking of her vows. The subject of open marriage would occasionally come up in our relationship, both before we were married and after. it was never in the context of "maybe we should consider this" but rather in the context of "I can't believe you did that in the past". I feel as I do then; swinging isn't something I have to have. If she wasn't comfortable with it, it would never happen. I never asked her, never suggested, never intimated that I would like her to do so. We got into this because my wife voiced interest rather out of the blue, shocking the heck out of me.
I don't feel the way I handled this was in any way dishonest, and neither does my wife, who values truth and honesty very, very highly.