Lucy has written an awesome post at her website (registration required but well worth it if you're interested in Trans201 type discussions) riffing off something I tweeted yesterday. I'm a bit embarrassed, because she's expanded my thought to encompass a whole range of ways in which trans people are viewed as defective cis people when I was thinking of a much narrower definition.
The thing is, even a lot of trans people tend to judge our bodies based on how closely we conform to cis expectations - in common parlance, "how well we pass". This isn't completely unreasonable, because we're safer, both physically and emotionally, if cis people read us as cis and gender us correctly, but I for one have internalised it in a very unhealthy way. I don't look at my body and say, "This is a pretty typical trans male body without HRT." I don't even say, "This is a body a lot of people will read as female, which sucks." I say, "What kind of man has these things on his chest? What kind of man has a cock you can't see unless you stick your nose right on it?" And then I stop looking at my body, because the differences between it and a cis male body make me doubt my manhood in all sorts of gross ways.
(I don't want to come across as minimising physical dysphoria. I know it's very painful for some trans people, but I don't really suffer from it. My discomfort all comes from a different source.)
The other thing I had in mind when I talked about "defective cis people" was the Negative Fertility Definition of gender. I've mostly heard it from transphobic radfems, but I'm sure there are others who use it as a justification for their bigotry. The problem transphobic radfems have is that most of their "reasons" why trans women don't count as women are also applicable to some cis women (as elaborated in this post.) In a search for ways to deny trans women's gender without offending the cis women they claim to be supporting, they've come up with the Negative Fertility Definition.
The Negative Fertility Definition basically says that the benchmark of being a man or a woman is the inability to reproduce like a woman or a man. It's not perfect for the transphobes' purposes, because it doesn't allow them to dismiss infertile trans people (at least without resorting to massive essentialist handwaves last seen from opponents of marriage equality), but it's guaranteed not to accidentally misgender any cis people. It is completely arbitrary - why make the definition of gender all about how you don't reproduce - but it's a lot harder to attack than, "How can someone be a woman if they have a structure in their body that produces testosterone?" (Fun fact: ovaries produce testosterone too.) I can see why they use it.
More broadly, trans people's reproductive status is one of the big things that breaks cis people's brains. We can't make babies the way cis people do, so the expectation is that we will just suck it up and live an infertile life. And for some trans people, that's fine: not everyone wants to make babies, and some are actively grossed out by the idea. But some trans people want to pass on our genes, want to have families that are not dependant on the good graces of a potentially cissexist adoption system, want, even to make babies. And it's pretty cruel to say that we can't because cis people the same gender as us aren't able to.
The idea of pregnancy has long been the only thing that let me reconcile myself to my body. It invites misgendering and it pumps out soul-destroying hormones, but it can grow a new person almost out of nothing. That's a pretty cool thing to be able to do. And I never felt more comfortable with the lumps on my chest than when they were producing high-quality baby food on demand. (This is why I was so resistant to weaning - "getting your body back" didn't seem to apply.) People want me to be apologetic or upset because these aren't things associated with male bodies, but they're amazing things. Why should I feel bad about having a body that can do them?
I have a trans male body. It has its own limitations and its own capabilities. It is not a defective cis male body.