These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Fridge Logic: Wait, doesn't GIR once get Zim to "dance" with him on the show without any apparent confusion?
And if Irkens are so freaked out about suicide, why does Zim almost self-destruct in the first episode?
The suicide thing might not have anything to do with the self-destruct mechanism. I imagine the self-destruct is more for emergencies. After all, not pressing it could very well end in a painful, messy death anyway (possibly leading to the death of several other Irkens, depending), so why not take your possible killers out with you?
Self-destructing is probably looked on as more favorable and honorable than not botching a mission.
Strangled by the Red String: Averted. Thirty chapters in Purple and Zim are considerably closer, but still acting like their usual, non-love-sick selves. Likewise there are so many side-plots that you can love this story even if you don't like the Zim/Purple romance.