While some people experience all gay attraction as the same, we do not. Cenelian relationships feel different than veldian relationships to us, just like how our relationships with woman-aligned people feel sapphic.
In particular, if my system is with a person who is unaligned genderqueer, there is a feeling of similarity between our and the other person's identity, by virtue of both of us knowing what it's like to have a non-normative identity or to relate your gender to things that are typically not thought of as genders.
However, the male component of our collective gender is stronger, more enduring, more defining, and more clearly-defined to us, such that a relationship with a man or man-aligned person feels MORE "same gender" than a relationship with an unaligned genderqueer person is.
This isn't to say that our relationships with non-male genderqueer people aren't gay, because they are. However, we feel that queer and non-conforming men - which, by virtue of us being a queer man with certain preferences, are the only men we would consider dating - have a more similar gender to us than people who do not have that as part of their gender at all.
Our MLM relationships, in-system, also seem to feature a stronger element of dominant and submissive relationship dynamics. This isn't necessarily in terms of an actual kink dynamic, although it often is. Rather, we tend to experience gay male relationships as more likely to or more naturally lending themselves to a dynamic in which one party is submissive and the other is dominant.
This may be because "masculinity" is a trait that most people who have it see it that you can have more or less of it than someone (e.g. some men are more masculine than others), whereas genderqueer people, at least those who are not aligned to a binary gender, usually do not see their gender alignment as something you can have "more" of - that is, genderqueer is either something you are or you aren't, but there aren't genderqueer people who are "more genderqueer" than others, like how there are some men who are "more masculine" than other men.
Therefore, it tends to be that in our MLM relationships, there is a partner who is more dominant and more (conventionally) masculine, and a partner who is more submissive and less masculine, or less conventionally masculine.
This way of thinking may seem to imply that we see dominance as masculine and submission as feminine, but this is only partly correct. It's true we acknowledge that dominance and being a leader are traditionally seen as a part of masculinity. However, we don't think that the absence of traditional masculinity is the presence of femininity, as we don't view men and women as opposites but rather two things that exist on a spectrum.
Furthermore, while we define CONVENTIONAL masculinity by society, we define ACTUAL masculinity by the much broader spectrum of ways that actual self-identified men actually behave, which includes basically everything. We also view the dominant and submissive nature of the participants of the relationship as something that can be exchanged or reversed at times.
While this doesn't mean that D/s kink is never part of our relationships with genderqueer people, dominant and submissive dynamics do not register as an INHERENT part of NLN relationships to us the way they do in MLM relationships. That is because we see different gender dynamics as existing between us and unaligned genderqueer people, which are different from the gender dynamics that exist between us and men.