SnK is the same as Naruto/Bleach in terms of its depth and quality of writing. That's why SnK has massive amount of shipping and it takes it very seriously, to the point where the threads, even during chapte release, are ONLY about shipping.
Now compare it to actual good shounen:>JJBA
Zero shipping at all in the two best parts (4 and 7 respectively), shipping only appeared during the bad times in the below average parts (5 and 6).>YYH
Only afflicted by fujo shipping, otherwise immune.>HxH
The best shonen (actually soft seinen) of all time powered entirely by its plot, supreme writing quality and insane depth. Any fujo shipping is treated like the insane crack for Japanese whales only, no one ever gives it any meaning.