... or the insulation on the anode wire was pinched, or any other number of things. Why take the chance? It takes literally 10 seconds to discharge the tube, so might as well do it.
You are completely right... seeing pinched HV cables is nightmarish.
And not seeing a pinch before handling the cables can result in a nice zapping... had that once.
But doing the discharge correctly and safely is difficult...
I don't consider it a safe practice to use a screwdriver that is certified to 5kV or typically much less.
If the wire has bad contact to the screwdriver or the ground clamp pops off, this can get DANGEROUS.
For this reason it was common in the TV industry not to discharge unless working at the HV components, as the discharge process requires a HV probe with at least 30kV insulation (see the image in this page), which will discharge the tube safely via the measuring divider (the tubes' capacity is "only" about one microfarad, and shorting caps is generally bad).
And often not mentioned in the "CRT discharge guides" also is the phenomenon of charge re-buildup, which is why you have to discharge several times over at least 1h, better more.
So it is often less risk and time consumption if you only discharge the CRT if really needed.
At least this was the perception with the 1960s and 1970s repair TV literature with which I learned to fix TVs.