This is the National use of force model used by all provinces that require Security personnel to be licensed.
Security personnel have the right to arrest someone under a citizens arrest. To use restraining devices I.E zip ties or hand cuffs, you must have a special licensing (at least in B.C but since AB uses protect licensing for all security I would assume they have it as well).
This guy is clearly active resistant allowing them to use controlling force, being a vocal victim during the restraining process while physically resisting is a very common thing these days. The only excess use of force I saw in that video was the one guy who came out of nowhere and started punching the guy in the sides to get his arms into an arrestable position, that is a total cop move and he isn't one, he is a licensed security guard. Aside from that, the whole situation went down right.
If the person was in fact trespassing with a banned substance they have every right to make that arrest. If his scissors were out in plain sight they could be considered a weapon. Especially if you have to ask this person to leave (acting as a passive resistant person while holding onto a potential weapon is the same as being assaultive due to the added threat).
I've never been a mall cop but I do have experience in security and more often than not, youtube videos only catch the aftermath of the "Victims" actions. Not the initial action and it is very trendy these days to "take it to the man" with video of police brutality or excessive force. Makes for a good lawsuit as well. And guys like that are very well aware of this. Easy way to get a good pay out. Seriously, I've worked in places that get sued on the regular without one of them getting a settlement or any after effects because the Judge tosses them while being mad he missed lunch for this waste of time.
As much as it appears these guys are Victims, they intend for it to look that way. No joke. But he got what he wanted in this situation because of that one guard who came in to massage his kidneys.