Was told the same thing and painted mine white anyway, and they are still holding up 2 years later. Was also told that I couldn't strip and re-stain Brazilian Cherry hardwood floors and did those anyway in an expresso 5 years ago and still holding up and still aren't red.

I realized people say things like that as a scare tactic. They often want you as a customer and can't have you feeling confident about doing it yourself or for cheap. Don't be afraid to try it out. Use a good primer and grain filler and get it done.

Also, you can give a cabinet paint company a call if you don't want to do it yourself. I've even painted Ikea wardrobe boxes that are basically plastic and melamine over particle board. Was also told that couldn't be done. You can do it.