The pot thing is I think the guy was a dealer and just using Halloween as an excuse but got too high himself …
Well, this click-bait listicle doesn’t really prove anything.
I suppose it may have happened at some point in history, but I’d venture that the odds of your kid getting a needle in a candy bar this Halloween are negligible.
Needles in Halloween candy are needlessly cruel, though ECT might be a treat for dealing with ones autumnal blues.
Yeah, I don’t recall getting “ect” in Halloween candy. Guess I was in the wrong neighborhood.
Quoth Snopes: many cases of tampered trick-or-treat loot involving the insertion of pins, needles, or razor blades have been documented.
“(In those instances where such an insertion could be traced back to a specific person, it was almost always some kid intent on freaking out either his little brother or his parents or getting the community in an uproar as his version of a cute Halloween “trick”…nearly all such reports of such rumors proved to be hoaxes…”
So, yeah, it appears that it started as a hoax, then was copied by some kids looking for a reaction, then there was a real case of it.
There was a comedian who suggested buying only apples and razor blades at a supermarket near Halloween to see the cashier’s reaction. I cannot remember who it was.
Why did you think it was b.s.? 
I’ve always wondered how one would insert a razor blade into an apple. It would probably be a wasted effort in the first place, as the kid would be more likely to throw it than eat it.
Because, as a whole, it is.
The snopes article cited earlier in the thread mentions exactly one documented case of actual tampering with random candy, rather than hoaxes, that if they did include tampering, was a one-off after the treat had been received. In 2000.