Because your argument is wrong.
How is my position is illogical?
If it looked like a bomb to the school authorities, they should have cleared the building before they called the police. This is been explained a number of times. I can explain it for you but I cannot understand it for you.
It seems you have some trouble understanding it yourself. Something can
look like a bomb without actually being a bomb, obviously so. For example:
This may
look like a bomb but anyone who sees this picture will likely not imagine that Adam West dressed up as batman would
actually carry a real explosive device and thus would conclude that it's most likely a prop. Likewise, someone who sees this device:
might conceivably think that it
looks like a bomb, but is not dangerous because of the obvious lack of any explosives. Now that it has been explained in terms a 14-year old child should understand, can we put this stupid argument to the rest finally? Nobody thought the "clock" was a real bomb at any point, nobody is claiming they thought it was a bomb, and that's why nobody evacuated the school or called the bomb squad.