My HP print service has always said colour for many years. I do not get bothered by it at all. Colour and color obviously means the same. You would need to ask HP why.
Samsung Print Service says "Colour" instead of "Color" primarily because Samsung is a global brand, and "colour" (with a 'u') is the standard British English/Commonwealth spelling, used in many regions where Samsung operates, while "color" is American English; the software often defaults to a non-US regional setting or general international standard, even if you're in a US locale. It's a localization choice reflecting widespread English usage, not necessarily an error.
