The confiscation was within the rules (as security staff anywhere have immense flexibility, which they can exercise when they perceive a possible need). This is what you'd hope and expect for people required to make potential life and death decisions on the spot.
The confiscation was sensible - you would not expect it with certainty, but should in no way be surprised when it happens.
After you've stopped snorting over the stupidity of that question, consider how most people would have answered a similar "boxcutter" question up until about the end of August 2001.
If you REALLY do not wish to lose such items check-in is a much safer choice.
I carried an unused ink-jet cartridge filling device Auckland-Brunei, Brunei-Hong Kong, Hong Kong - China, China internal flight Guangzho to Guilin. I ATTEMPTED to carry it on the return flight Guilin-Guanzho. The security officer sought to confiscate it, along with a short bladed "Swiss Army Knife" that I had stupidly failed to pack in check-in luggage. I accepted the loss of the Knife (about as offensive as your scissors) as being my fault.
I argued that the ink jet cartridge refiller with 3 x maybe 10mm small diameter needles inside a shell was utterly harmless.
He stood firm.
I called him a fascist moron.
He stood firm, and was not moved by my apposite but immensely unwise abuse (the ONLY time I have ever spoken heatedly at security men, let alone called them names).
I wonder what they did with the refiller :-)?
If you can lose a device with 3 x 10mm sheathed needles then your vicious stabbing weapon is an obvious candidate!
Think yourself fortunate that they let you retain the dangerous set of 5 metal piercing implements also shown in your photo!
A fair bit of the above was written, as you may have noted, somewhat 'tongue in cheek'.
Only somewhat. Security does what security does. Your job is to outthink them in advance, as complaining afterwards has no positive effect whatsoever.