Baalei teshuva are probably in the same boat as the conversion candidates, but at least they're still Jewish at the end of the day. Even the people who act like "modern orthodox" is a slur will still recognize the BTs as "Jews." But choosing to convert "modern orthodox" is a hard choice for many conversion candidates.
In the quest for the "unquestionable conversion," conversion candidates are feeling pushed further and further to the "right" of orthodox Judaism. Each chumrah feels like another piece of armor to protect against others' questioning their Jewishness. [But note that more people convert "modern orthodox" or "just plain orthodox" than any other group, and people in modern orthodox communities are usually not the ones whose Jewishness is questioned. It is usually the ultra-orthodox communities these candidates seek so hard to join.]
I've chosen to stop looking for the unquestionable conversion. As far as I can tell, they're ALL questionable. So instead, I will take the time to find the community that is best for me hashkafically. And that is the modern orthodox community.
But what are people insulting when they call people "modern"? It seems that the insult version of the phrase emphasizes the word "modern" orthodox. I know that my own stereotype of the "bad" kind of modern orthodox is someone who keeps kosher and Shabbat, but not much else. In many ways, a kind of "culturally orthodox" person. I think that the groups who are so opposed to modern orthodox Jews have this perception.
But that is not who I am. And that is not who the other modern orthodox people in my community are.
So what IS modern orthodoxy to someone who is often mistaken as being "too frummy" for the MO crowd? [Apparently the most common first impression that people have of me is "frummy" and "super frummy."]
I don't believe that the "secular world" is evil and to be avoided. I don't believe that there is a clear line "bein kodesh l'chol." Torah is everywhere I look. Interactions with people who've never even heard the word "Torah" may teach me more Torah than a two-hour halacha shiur. Television shows or movies can do the same. Working in a secular profession in a secular workplace allows me to be a kiddush Hashem in addition to being it being yet another source of Torah.
Put another way, ANYONE can be "modern," no matter their hashkafah. There are even some people who call themselves "modern yeshivish," despite the fact that many people's stereotypes of yeshivish would negate the ideas of "modern"-ness.
I think that insulating myself and alienating the non-Jewish aspects of my life would remove many of the best Torah sources in my life.
As a convert, I think this will be even more important in my life. Alienating my family would be a chilul Hashem. I have this family because Hashem has decided it is the best family for me. The same for the friends from my "prior" life (granted, I've been "Jewishly affiliated" basically my entire adult life). I also do not believe that the experiences of my pre-orthodox life are less valuable because there was "less Torah" in it.
We are the product of our experiences. I must be just as discerning in the "secular" things that I see and do as I must be in the things labeled as "Torah." That requires the opposite realization that maybe things labeled as "Torah" are bad influences. People, groups, and ideas that are even more damaging than any R rated movie...promoting hatred, fear, and sinas chinam.
In my opinion, modern orthodoxy is about being willing to see Torah in everything, and that allows me to see the inherent value in everything. I consider people, things, and ideas individually, rather than shutting them out as groups based on stereotypes. By extension, that is why I hesitate to accept the halachic "ruling" of those who would "pull" my conversion for working in a secular profession, owning a television, or using the internet.
But I really prefer the term "just plain orthodox." Too bad everyone insists on making me choose a box.