[Agema]

It's chance, and the errors in human perception relating to chance.

What happens is that people very keenly remember when their expensive super-SC fails that one time, especially when the fail is catastrophic and results in autodeath, and more so if it happens early in a battle.

People forget that that same SC might have already been subject to many MR rolls over time and passed them all; or they forget they have many SCs over the course of playing Dom3 who have passed hundreds of such rolls between them and it's only that one that has failed catastrophically. They may forget the times that SCs fail a MR check but it was for something trivial like taking damage from an astral geyser, and so lose perspective of how easy it can be to fail an MR roll.

Alternatively, you can view it this way. If you've got a community of hundreds, each of whom is running a few games, each game with a few SCs, if all those SCs have a 1/1000 chance of failing an MR roll, it's actually very likely at least one SC walks into a battle and fails an MR roll with a disasterous result, because you've got over 1000 SCs facing MR rolls.