Remember: Strings do not and cannot have 'scale length', they only have 'winding length'. Any mention of 'scale length' by a brand is just an unreliable guide to the bass guitar scale length the winding length is likely to be compatible with.
You cannot use long scale strings and just cut them down.
True that cutting strings anywhere other than the silked/tapered section will ruin the string. However you link this statement to:
1. Strings are wound at playing tension. When used on a shorter scale they are never pulled to proper tension and sound muddy.
Tension is independent of, and unrelated to, string winding length.
The tension of a string depends on bass guitar scale length, pitch and gauge only. Not the string winding length. So-called 'medium scale' strings and 'long scale' strings will have the same tensions.
Strings are wound at a manufacturing tension that is usually lower than the intended tension (intended tension varies according to what set the gauge is in), this is done to make them sound good when used at lower tensions. For example a .050 can be a tight G in one set or an extra light D in another set, so it is wound at a low-as-possible manufacturing tension to work well at low tension at D. Players often detune their strings too.
A medium or short scale bass guitar does not make a huge difference to tension so medium gauge strings are likely to still exceed their manufacturing tension.
Although exceeding the winding tension is helpful, it does not make a big difference and will not make a string 'muddy', just a little stiffer, a little darker, a little more inharmonic.