I always tinkered with electronics as a kid, and these protections against tampering were easily defeated by melting the cap of a bic pen with a lighter.
Build your tools :)
I find it sort of amusing that the idea of a "security torx" is that people won't be able to insert a flat or regular torx. Every bit set I've seen the last 10 years have had security torx included, so beating the "security" just require a trip to the hardware store.
I tried that -- went to Lowes I believe, and asked a hardware guy there if they carried the bits. He then proceeded to treat me as if I was some sort of criminal, informing me that those security screws are there for a reason. I'm sorry, but it is not against any criminal code that I know of to want to fix your own oscillating fan. Of course I see that they have it on their web site, so I should have just brought up that page on my cell phone (or part number) and be done with it.
The people working at those stores are really just a random smattering of warm bodies to fill a position. It appears you ran into the type of person who wants to play macho man from a limited knowledge set - don't take it personally. Go back the next day and a different person might [know exactly where the bits are, pass you off to someone else in the store, not know what a screwdriver is, or be curious about what you're fixing and recommend a different place you can actually obtain them]. Companies wanted replaceable minimum wage workers and that's what they got.
We must buy different bit sets. I go through a lot of dewalt bit sets in all shapes and sizes of plastic yellow boxes and I have never seen a security torx bit included. What bit sets do you purchase?
I have a handy little computer repair set made by Tekton[1]. All its Torx bits are security ones. (note they call them "Star" and "Tamper Star" for trademark reasons I suppose)