don't judge people through coloured-spectacles

The more common phrase is rose-coloured glasses. if someone thinks about or looks at something with rose-coloured glasses, they think it is more pleasant than it really is.

The phrase coloured-spectacles is also acceptable but not as common and means the same thing.

It makes sense to me.

What it suggests is that the best judgments are those made without any form of prejudice or bias. If your have a prejudice or bias then the way in which you view them may be 'coloured' by that bias.

Easier said than done if you ask me!

if, like me, you can

bring a shade of grey to any colourful spectacle

then you know it makes sense