Maybe it's because I'm an ENFP... but I see this as a perfectly polite, valid question.

I don't see what everyone's going on about...
I know a lot of SJs, and my whole theory is that it must suck to be Se or Si dom where Ne or Ni would be more useful, and vice versa.
Other types always see something about types they're not a member of as "sucking" because they don't like to operate that way. However, I also recognize that sometimes being an NF sucks (everyone inevitably hurts your feelings, no one seems to understand you, and if you do feel depressed there's a nasty little voice in your head informing you that everyone thinks you're pathetic). I've heard other types say that sometimes being an XX sucks, and the reasons they give usually aren't the ones I would have expected.
I would think that it would suck to be an SJ because they get a lot of crap about being boring, and it's usually not true.