I guess if we said there is no point having security checks because engineers can bring pointy obects in, then we would all be say that it's rediculous that ANYONE can walk through security with a knife, even office staff working airside.
There has to be a certain 'do as much as practically possible' attitude to this. You're not going to plug all the wholes, but you're a fool for not trying.
Having said that, Dublin security is laughable sometimes. I once heard an engineer walked through with a leatherman and security asked him what it was. He said "a leatherman, you know, a knife and pliers and all that in one tool!" the security man just said "thats ok, now take your shoes off and put them through the scanner". The engineer replied "Why? What are you hoping to find, a knife?"
I think it's hilarious but it does show you that security can loose focus on what they are trying to achieve. But hey, hats off, they are aiming to achieve the impossible.