I was a kid at the time. I missed the live broadcast because I was on a Scouts activity. However, although I remember the tragic discussion in the news about the poor man who committed suicide, and some of the backlash and complaints about people who thought it was real, I didn't experience any of that.
Kids I knew all seemed to be aware of it being a Screen One play (and it was trailed heavily as being in the Screen One slot, even if the trails played it as if it was live broadcast from "the most haunted house in Britain", or some such).
Mostly the discussion was how many times people spotted Pipes, and how often he actually appeared, with a suggestion the film was "cursed" in the same way the Exorcist was considered to have spooky effects.
However... I do remember there being shows around he same time, there were shows in the style that Ghostwatch tried to ape for the studio sections. I have a fairly vivid memory of a live show with call ins around the same time, where psychics were discussing a supposedly cursed and haunted skeleton of a "small alien" or "shrunken sailor", that turned out to be (when investigated by a doctor) the skeleton of a developing foetus, preserved by a teaching hospital. Other shows had phone in sections asking to solve strange mysteries, such as a vanishing mansion house, a lost village, and other things many people remembered that were not there (which today would be examples of the Mandella effect).
I am not suggesting memories of multiple shows got bound together, simply that for some people perhaps the first two thirds of Ghostwatch might not have seemed as far from what some expected from "real" shows, as it may now seem. But... As soon as Sarah Greene and Parkinson turned up on TV alive and well, the idea of it being real should have been blown away.
Personally, as far as cruel hoaxes go, I was more disturbed by Paul Daniel's series seeming to end on a trick going wrong. That really did leave me uncomfortable as a kid!