The thing about labels (I think) i that they're just models, so they never fully represent the thing they're modelling - which is people. This means they more often than not need some further explanation, as very often the same label means different things from one person to the next. So for me, it's always interesting to find out what people like to all themselves and why, but I'm careful not to hang labels on people that they haven't chosen for themselves.
I'm one of these people that dislike the term "transsexual", but rather than say I'm transgender, I'm more likely to say "I'm going through a gender transition". I am, however, and will remain, very genderqueer - a label that to me suggests a relationship with gender that doesn't fit social expectations, in whatever way. This label fits me because I'm a trans tomboy who, post-surgery, is very likely to be packing sometimes

. I'm not transitioning in order to stop being genderqueer - I'm transitioning because I'm a genderqueer woman with the wrong body parts. Ad yes, as someone else here so perfectly expressed it recently, sometimes I feel like a trans man trapped in a man's body. It doesn't have to make sense.
I'm also queer - but I really dislike that word (even though for some reason, genderqueer doesn't bother me), because other people used it on me like a weapon when I was younger. Perhaps it's a generational thing (queer seems to have a much broader meaning for younger folk than me) but to my mind's ears, queer just relates to sexual orientation. So I'm not comfortable with calling myself queer, and don't want to be called that - I'm a celibate polysexual

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As to the original question - there's a lot of contention because people get overidentified with their identities and labels, I think. So if someone who identifies as genderqueer doesn't feel they belong under the trans umbrella, that's fine with me. The umbrella is a very nebulous device, to my mind just there to protect us all from other people's spit. It's not a corral.
PS I've been labelling myself as
womandrogyne for a while, because I'm somewhere between woman and androgyne - but then I came up with
trandrogyne (because I wanted to include my transness), and now I want a label that's part-way between womandrogyne and trandrogyne, so I ended up with
transwomandrogyne, and this is just getting silly

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