Kabbolistically, a person should wear only white (davka)on shabbos – seems it represents chesed (while black is for gevuros). Those that are noheg al pi kabbalah should follow their minhagim. Unless you consistently follow kabbalah minhagim – it is irrelevant to you.
In any event, the white (and not “colors”) is consistent with the color scheme of other yidden who wear white and black.
Regarding the so-called “famous portrait of the Tzemach Tzedek (3rd Rebbe of Lubavitch)…always wearing white clothes” – I once saw this DRAWING (not a photograph) and it seemed to have been sketched in black and white, thus the fact that there was no color in his hat or bekkishe is no rayah at all.
Some Rosh Yeshivas, as in CHaim Berlin etc. on shabbos would wear their talis by folding the black stripes on their shoulder UNDER the talis so that only the white part of the talis showed. This way they were yotzeh the kabbalistic need to “wear white” on shabbos.
On yomim noroyim (strictly mmarried men) wear kittels, to be yotzeh wearing white (among other reasons) but no hakpodeh to wear ONLY white (pants, shoes etc).
Wearing gray and/or blue is stam being poetz geder, and as generations decline, following your derech of prikus ol of the black-white malbush, your grandchildren may wear orange and pink r”l. That can happen when we start making minor adjustments to “al titosh toras imecha”.
If you leave a straight path by just one degree, after a few miles you won’t be able to see the path you left.