Blue toner evens out coppery colors, so if they had any bleaching done to lighten the non-gray and homogenize their color, the blue toner would even it out.
However, grey hair that has been “opened up” with chemical treatment but has no color of its own to compliment/cover will pick up a blue tint.
Idk why it’s not common anymore; maybe because stylists know better, maybe products are better, or maybe they just use pre-formulated dyes now instead of multi-step.
In the UK, it was standard for a while for women with grey/white hair to get a “blue rinse” which presumably did something to the look of the hair.
As you say, the same population were generally held to have reactionary views, part of the ‘drift right’.
They therefore became known as the blue rinse brigade, a right of centre voting block.
Blue toner evens out coppery colors, so if they had any bleaching done to lighten the non-gray and homogenize their color, the blue toner would even it out.
However, grey hair that has been “opened up” with chemical treatment but has no color of its own to compliment/cover will pick up a blue tint.
Idk why it’s not common anymore; maybe because stylists know better, maybe products are better, or maybe they just use pre-formulated dyes now instead of multi-step.