Probably because the SPL is just as bad as the MLS so they're used to playing at a crap standard.
Club football in Scotland is nowhere close to that bad, but as discussed in these pages, there's ample room for it to fall to such an abominable depth and persuasive evidence of an ever gathering downward momentum pushing it in that direction (and they might consider bringing it over here and trying to play in North American summer heat and humidity, which in all genuine possibility could suffice to kill it off once and for all)
And anyway I'd be remiss if I were to neglect to mention that it's just MLS --there's no the to it