The only time it's noticeable is when it's on the trailer, and after you're thankful you had a keel guard on.
You MAY be able to get a paint that's made for that material, but with the conditions this will be under, I would highly doubt it will last longer than a season, if that. You'll then be painting this thing every year to keep up appearances. If I were in your shoes, I'd skip any notion of coloring it to match - even a red keel guard is likely to not match exactly, AND it can/will fade over time, so that it no longer matches over time.
I'd learn to love the protection it gives, and the contrast/match with the hull colors as they are. The only other alternative is what
@Ronnie suggested - remove it, at more expense, along with the hassle and struggle of removal, and replace it, likely with a red that won't be a perfect match, and therefore just as noticeable or aggravating as the white currently is.
I also would have specified the color of keel guard you wanted. IF you did that, and they didn't follow your instructions, I'd be taking it back for removal and replacement with the proper one. If you DIDN'T do that, well, that's on you. Assuming they'd do what you would have, can only be accomplished with voicing that directive prior to installation. At the very least, you could have specified that they call you with info about the keel guard. There's no reason to assume they'd color match the red, since the white still mates with the rest of the colorway of the boat, and as stated here, it'll be below the waterline, and out of sight.
I know it sucks to see that it doesn't match what you were expecting, but without laying out your expectations, no matter how small, they were never given guidance as to what you were looking for. Common sense to you included matching the color. Common sense to them meant protecting the keel. "Common sense" is only common if it's always done one certain specific way, and I've seen more than one boat with a contrasting keel guard. To me, a black one would have faded into the background better than the white, but because red is so hard to match, I wouldn't have chosen it to begin with, so common sense, in this case, can't be assumed, and must be specified to either put on what you want, or to not do it altogether until the specified color can be obtained.
Not having that color isn't an excuse, since I can find a red keel guard in several different lengths on Amazon, and all can be at my doorstep in 2 days. I will also note, NONE of the red keel guards seem like they'd match your boat. Black or grey are similar in speed of delivery.
